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Kosgei J, Gimnig JE, Moshi V, Omondi S, McDermott DP, Donnelly MJ, Ouma C, Abong'o B, Ochomo E. Comparison of different trapping methods to collect malaria vectors indoors and outdoors in western Kenya. Malar J 2024; 23:81. [PMID: 38493098 PMCID: PMC10943837 DOI: 10.1186/s12936-024-04907-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 03/11/2024] [Indexed: 03/18/2024] Open
Abstract
BACKGROUND Vector surveillance is among the World Health Organization global vector control response (2017-2030) pillars. Human landing catches are a gold standard but difficult to implement and potentially expose collectors to malaria infection. Other methods like light traps, pyrethrum spray catches and aspiration are less expensive and less risky to collectors. METHODS Three mosquito sampling methods (UV light traps, CDC light traps and Prokopack aspiration) were evaluated against human landing catches (HLC) in two villages of Rarieda sub-county, Siaya County, Kenya. UV-LTs, CDC-LTs and HLCs were conducted hourly between 17:00 and 07:00. Aspiration was done indoors and outdoors between 07:00 and 11:00 a.m. Analyses of mosquito densities, species abundance and sporozoite infectivity were performed across all sampling methods. Species identification PCR and ELISAs were done for Anopheles gambiae and Anopheles funestus complexes and data analysis was done in R. RESULTS Anopheles mosquitoes sampled from 608 trapping efforts were 5,370 constituting 70.3% Anopheles funestus sensu lato (s.l.), 19.7% Anopheles coustani and 7.2% An. gambiae s.l. 93.8% of An. funestus s.l. were An. funestus sensu stricto (s.s.) and 97.8% of An. gambiae s.l. were Anopheles arabiensis. Only An. funestus were sporozoite positive with 3.1% infection prevalence. Indoors, aspiration captured higher An. funestus (mean = 6.74; RR = 8.83, P < 0.001) then UV-LT (mean = 3.70; RR = 3.97, P < 0.001) and CDC-LT (mean = 1.74; RR = 1.89, P = 0.03) compared to HLC. UV-LT and CDC-LT indoors captured averagely 0.18 An. arabiensis RR = 5.75, P = 0.028 and RR = 5.87, P = 0.028 respectively. Outdoors, UV-LT collected significantly higher Anopheles mosquitoes compared to HLC (An. funestus: RR = 5.18, P < 0.001; An. arabiensis: RR = 15.64, P = 0.009; An. coustani: RR = 11.65, P < 0.001). Anopheles funestus hourly biting indoors in UV-LT and CDC-LT indicated different peaks compared to HLC. CONCLUSIONS Anopheles funestus remains the predominant mosquito species. More mosquitoes were collected using aspiration, CDC-LTs and UV-LTs indoors and UV-LTs and CD-LTs outdoors compared to HLCs. UV-LTs collected more mosquitoes than CDC-LTs. The varied trends observed at different times of the night suggest that these methods collect mosquitoes with diverse activities and care must be taken when interpreting the results.
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Affiliation(s)
- Jackline Kosgei
- Entomology Section, Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya.
- Department of Biomedical Sciences and Technology, Maseno University, Maseno, Kenya.
| | - John E Gimnig
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Vincent Moshi
- Entomology Section, Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Seline Omondi
- Entomology Section, Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Daniel P McDermott
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Collins Ouma
- Department of Biomedical Sciences and Technology, Maseno University, Maseno, Kenya
| | - Bernard Abong'o
- Entomology Section, Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Eric Ochomo
- Entomology Section, Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya.
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Kamya MR, Nankabirwa JI, Arinaitwe E, Rek J, Zedi M, Maiteki-Sebuguzi C, Opigo J, Staedke SG, Oruni A, Donnelly MJ, Greenhouse B, Briggs J, Krezanoski PJ, Bousema T, Rosenthal PJ, Olwoch P, Jagannathan P, Rodriguez-Barraquer I, Dorsey G. Dramatic resurgence of malaria after 7 years of intensive vector control interventions in Eastern Uganda. medRxiv 2024:2024.03.15.24304352. [PMID: 38559091 PMCID: PMC10980127 DOI: 10.1101/2024.03.15.24304352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Background Tororo District, Uganda experienced a dramatic decrease in malaria burden from 2015-19 following 5 years of indoor residual spraying (IRS) with carbamate (Bendiocarb) and then organophosphate (Actellic) insecticides. However, a marked resurgence occurred in 2020, which coincided with a change to a clothianidin-based IRS formulations (Fludora Fusion/SumiShield). To quantify the magnitude of the resurgence, investigate causes, and evaluate the impact of a shift back to IRS with Actellic in 2023, we assessed changes in malaria metrics in regions within and near Tororo District. Methods Malaria surveillance data from Nagongera Health Center, Tororo District was included from 2011-2023. In addition, a cohort of 667 residents from 84 houses was followed from August 2020 through September 2023 from an area bordering Tororo and neighboring Busia District, where IRS has never been implemented. Cohort participants underwent passive surveillance for clinical malaria and active surveillance for parasitemia every 28 days. Mosquitoes were collected in cohort households every 2 weeks using CDC light traps. Female Anopheles were speciated and tested for sporozoites and phenotypic insecticide resistance. Temporal comparisons of malaria metrics were stratified by geographic regions. Findings At Nagongera Health Center average monthly malaria cases varied from 419 prior to implementation of IRS; to 56 after 5 years of IRS with Bendiocarb and Actellic; to 1591 after the change in IRS to Fludora Fusion/SumiShield; to 155 after a change back to Actellic. Among cohort participants living away from the border in Tororo, malaria incidence increased over 8-fold (0.36 vs. 2.97 episodes per person year, p<0.0001) and parasite prevalence increased over 4-fold (17% vs. 70%, p<0.0001) from 2021 to 2022 when Fludora Fusion/SumiShield was used. Incidence decreased almost 5-fold (2.97 vs. 0.70, p<0.0001) and prevalence decreased by 39% (70% vs. 43%, p<0.0001) after shifting back to Actellic. There was a similar pattern among those living near the border in Tororo, with increased incidence between 2021 and 2022 (0.93 vs. 2.40, p<0.0001) followed by a decrease after the change to Actellic (2.40 vs. 1.33, p<0.001). Among residents of Busia, malaria incidence did not change significantly over the 3 years of observation. Malaria resurgence in Tororo was temporally correlated with the replacement of An. gambiae s.s. by An. funestus as the primary vector, with a marked decrease in the density of An. funestus following the shift back to IRS with Actellic. In Busia, An. gambiae s.s. remained the primary vector throughout the observation period. Sporozoite rates were approximately 50% higher among An. funestus compared to the other common malaria vectors. Insecticide resistance phenotyping of An. funestus revealed high tolerance to clothianidin, but full susceptibility to Actellic. Conclusions A dramatic resurgence of malaria in Tororo was temporally associated with a change to clothianidin-based IRS formulations and emergence of An. funestus as the predominant vector. Malaria decreased after a shift back to IRS with Actellic. This study highlights the ability of malaria vectors to rapidly circumvent control efforts and the importance of high-quality surveillance systems to assess the impact of malaria control interventions and generate timely, actionable data.
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Affiliation(s)
- Moses R. Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda
- School of Medicine, Makerere University Kampala, Uganda
| | - Joaniter I. Nankabirwa
- Infectious Diseases Research Collaboration, Kampala, Uganda
- School of Medicine, Makerere University Kampala, Uganda
| | | | - John Rek
- Infectious Diseases Research Collaboration, Kampala, Uganda
- National Malaria Control Division, Ministry of Health, Kampala, Uganda
| | - Maato Zedi
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Catherine Maiteki-Sebuguzi
- Infectious Diseases Research Collaboration, Kampala, Uganda
- National Malaria Control Division, Ministry of Health, Kampala, Uganda
| | - Jimmy Opigo
- National Malaria Control Division, Ministry of Health, Kampala, Uganda
| | - Sarah G. Staedke
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Ambrose Oruni
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Martin J. Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Bryan Greenhouse
- Department of Medicine, University of California San Francisco, San Francisco, California, USA
| | - Jessica Briggs
- Department of Medicine, University of California San Francisco, San Francisco, California, USA
| | - Paul J. Krezanoski
- Department of Medicine, University of California San Francisco, San Francisco, California, USA
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Netherlands
| | - Philip J. Rosenthal
- Department of Medicine, University of California San Francisco, San Francisco, California, USA
| | - Peter Olwoch
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Prasanna Jagannathan
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University, USA
| | | | - Grant Dorsey
- Department of Medicine, University of California San Francisco, San Francisco, California, USA
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Lucas ER, Nagi SC, Kabula B, Batengana B, Kisinza W, Egyir-Yawson A, Essandoh J, Dadzie S, Chabi J, Van't Hof AE, Rippon EJ, Pipini D, Harding NJ, Dyer NA, Clarkson CS, Miles A, Weetman D, Donnelly MJ. Copy number variants underlie the major selective sweeps in insecticide resistance genes in Anopheles arabiensis from Tanzania. bioRxiv 2024:2024.03.11.583874. [PMID: 38559088 PMCID: PMC10979859 DOI: 10.1101/2024.03.11.583874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
To keep ahead of the evolution of resistance to insecticides in mosquitoes, national malaria control programmes must make use of a range of insecticides, both old and new, while monitoring resistance mechanisms. Knowledge of the mechanisms of resistance remains limited in Anopheles arabiensis, which in many parts of Africa is of increasing importance because it is apparently less susceptible to many indoor control interventions. Furthermore, comparatively little is known in general about resistance to non-pyrethroid insecticides such as pirimiphos-methyl (PM), which are crucial for effective control in the context of resistance to pyrethroids. We performed a genome-wide association study to determine the molecular mechanisms of resistance to deltamethrin (commonly used in bednets) and PM, in An. arabiensis from two regions in Tanzania. Genomic regions of positive selection in these populations were largely driven by copy number variants (CNVs) in gene families involved in resistance to these two insecticides. We found evidence of a new gene cluster involved in resistance to PM, identifying a strong selective sweep tied to a CNV in the Coeae2g-Coeae6g cluster of carboxylesterase genes. Using complementary data from An. coluzzii in Ghana, we show that copy number at this locus is significantly associated with PM resistance. Similarly, for deltamethrin, resistance was strongly associated with a novel CNV allele in the Cyp6aa / Cyp6p cluster. Against this background of metabolic resistance, target site resistance was very rare or absent for both insecticides. Mutations in the pyrethroid target site Vgsc were at very low frequency in Tanzania, yet combining these samples with three An. arabiensis individuals from West Africa revealed a startling diversity of evolutionary origins of target site resistance, with up to 5 independent origins of Vgsc-995 mutations found within just 8 haplotypes. Thus, despite having been first recorded over 10 years ago, Vgsc resistance mutations in Tanzanian An. arabiensis have remained at stable low frequencies. Overall, our results provide a new copy number marker for monitoring resistance to PM in malaria mosquitoes, and reveal the complex picture of resistance patterns in An. arabiensis.
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Affiliation(s)
- Eric R Lucas
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Sanjay C Nagi
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Bilali Kabula
- National Institute for Medical Research, Amani Research Centre, P.O. Box 81, Muheza, Tanzania
| | - Bernard Batengana
- National Institute for Medical Research, Amani Research Centre, P.O. Box 81, Muheza, Tanzania
| | - William Kisinza
- National Institute for Medical Research, Amani Research Centre, P.O. Box 81, Muheza, Tanzania
| | | | - John Essandoh
- Department of Biomedical Sciences, University of Cape Coast, Cape Coast, Ghana
| | - Sam Dadzie
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Joseph Chabi
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Arjen E Van't Hof
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branišovská 31, 370 05 České Budějovice, Czech Republic
| | - Emily J Rippon
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Dimitra Pipini
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Nicholas J Harding
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
| | - Naomi A Dyer
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Chris S Clarkson
- Wellcome Sanger Institute, Hinxton, Cambridge CB10 1SA, United Kingdom
| | - Alistair Miles
- Wellcome Sanger Institute, Hinxton, Cambridge CB10 1SA, United Kingdom
| | - David Weetman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
- Wellcome Sanger Institute, Hinxton, Cambridge CB10 1SA, United Kingdom
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Ayo D, Onyige I, Okoth J, Musasizi E, Oruni A, Ramjith J, Arinaitwe E, Rek JC, Drakeley C, Staedke SG, Donnelly MJ, Bousema T, Conrad M, Blanken SL. Susceptibility of Anopheles gambiae to Natural Plasmodium falciparum Infection: A Comparison between the Well-Established Anopheles gambiae s.s Line and a Newly Established Ugandan Anopheles gambiae s.s. Line. Am J Trop Med Hyg 2024; 110:209-213. [PMID: 38150729 PMCID: PMC10859803 DOI: 10.4269/ajtmh.23-0203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 09/23/2023] [Indexed: 12/29/2023] Open
Abstract
Much of our understanding of malaria transmission comes from mosquito feeding assays using Anopheles mosquitoes from colonies that are well adapted to membrane feeding. This raises the question whether results from colony mosquitoes lead to overestimates of outcomes in wild Anopheles mosquitoes. We successfully established an Anopheles colony using progeny of wild Anopheles gambiae s.s. mosquitoes (Busia mosquitoes) and directly compared their susceptibility to infection with Plasmodium falciparum with the widely used An. gambiae s.s. mosquitoes (Kisumu mosquitoes) using gametocyte-infected Ugandan donor blood. The proportion of infectious feeds did not differ between Busia (71.8%, 23/32) and Kisumu (68.8%, 22/32, P = 1.00) mosquitoes. When correcting for random effects of donor blood, we observed a 23% higher proportion of infected Busia mosquitoes than infected Kisumu mosquitoes (RR, 1.23; 95% CI, 1.10-1.38, P < 0.001). This study suggests that feeding assays with Kisumu mosquitoes do not overestimate outcomes in wild An. gambiae s.s. mosquitoes, the mosquito species most relevant to malaria transmission in Uganda.
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Affiliation(s)
- Daniel Ayo
- Infectious Diseases Research Collaboration, Nagongera Hospital, Tororo, Uganda
| | - Ismail Onyige
- Infectious Diseases Research Collaboration, Nagongera Hospital, Tororo, Uganda
| | - Joseph Okoth
- Infectious Diseases Research Collaboration, Nagongera Hospital, Tororo, Uganda
| | - Eric Musasizi
- Infectious Diseases Research Collaboration, Nagongera Hospital, Tororo, Uganda
| | - Ambrose Oruni
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Jordache Ramjith
- Department for Health Evidence, Radboud University Medical Center, Nijmegen, Netherlands
| | - Emmanuel Arinaitwe
- Infectious Diseases Research Collaboration, Nagongera Hospital, Tororo, Uganda
| | - John C. Rek
- Infectious Diseases Research Collaboration, Nagongera Hospital, Tororo, Uganda
| | - Chris Drakeley
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Sarah G. Staedke
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Martin J. Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Nijmegen Medical Center, Nijmegen
| | - Melissa Conrad
- Department of Medicine, San Francisco General Hospital, University of California, San Francisco, California
| | - Sara Lynn Blanken
- Department of Medical Microbiology, Radboud University Nijmegen Medical Center, Nijmegen
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Nagi SC, Lucas ER, Egyir-Yawson A, Essandoh J, Dadzie S, Chabi J, Djogbénou LS, Medjigbodo AA, Edi CV, Ketoh GK, Koudou BG, Ashraf F, Clarkson CS, Miles A, Weetman D, Donnelly MJ. Parallel evolution in mosquito vectors - a duplicated esterase locus is associated with resistance to pirimiphos-methyl in An. gambiae. bioRxiv 2024:2024.02.01.578361. [PMID: 38352547 PMCID: PMC10862845 DOI: 10.1101/2024.02.01.578361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/24/2024]
Abstract
The primary control methods for the African malaria mosquito, Anopheles gambiae, are based on insecticidal interventions. Emerging resistance to these compounds is therefore of major concern to malaria control programmes. The organophosphate, pirimiphos-methyl, is a relatively new chemical in the vector control armoury but is now widely used in indoor residual spray campaigns. Whilst generally effective, phenotypic resistance has developed in some areas in malaria vectors. Here, we used a population genomic approach to identify novel mechanisms of resistance to pirimiphos-methyl in Anopheles gambiae s.l mosquitoes. In multiple populations, we found large and repeated signals of selection at a locus containing a cluster of detoxification enzymes, some of whose orthologs are known to confer resistance to organophosphates in Culex pipiens. Close examination revealed a pair of alpha-esterases, Coeae1f and Coeae2f, and a complex and diverse pattern of haplotypes under selection in An. gambiae, An. coluzzii and An. arabiensis. As in Cx. pipiens, copy number variation seems to play a role in the evolution of insecticide resistance at this locus. We used diplotype clustering to examine whether these signals arise from parallel evolution or adaptive introgression. Using whole-genome sequenced phenotyped samples, we found that in West Africa, a copy number variant in Anopheles gambiae is associated with resistance to pirimiphos-methyl. Overall, we demonstrate a striking example of contemporary parallel evolution which has important implications for malaria control programmes.
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Affiliation(s)
- Sanjay C. Nagi
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Eric R. Lucas
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | | | - John Essandoh
- Department of Biomedical Sciences, University of Cape Coast, Cape Coast, Ghana
| | - Samuel Dadzie
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Joseph Chabi
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Luc S. Djogbénou
- Tropical Infectious Diseases Research Center (TIDRC), Université d’Abomey-Calavi (UAC), 01 B.P. 526 Cotonou, Benin
| | - Adandé A. Medjigbodo
- Tropical Infectious Diseases Research Center (TIDRC), Université d’Abomey-Calavi (UAC), 01 B.P. 526 Cotonou, Benin
| | - Constant V. Edi
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, 01 BP 1303 Abidjan, Côte d’Ivoire
| | - Guillaume K. Ketoh
- Laboratory of Ecology and Ecotoxicology, Department of Zoology, Faculty of Sciences, Université de Lomé, 01 B.P. 1515 Lomé, Togo
| | - Benjamin G. Koudou
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, 01 BP 1303 Abidjan, Côte d’Ivoire
| | - Faisal Ashraf
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Chris S. Clarkson
- Wellcome Sanger Genomic Surveillance Unit, Wellcome Sanger Institute, Hinxton, Cambridge, CB10 1RQ, UK
| | - Alistair Miles
- Wellcome Sanger Genomic Surveillance Unit, Wellcome Sanger Institute, Hinxton, Cambridge, CB10 1RQ, UK
| | - David Weetman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Martin J. Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
- Wellcome Sanger Genomic Surveillance Unit, Wellcome Sanger Institute, Hinxton, Cambridge, CB10 1RQ, UK
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Dyer NA, Lucas ER, Nagi SC, McDermott DP, Brenas JH, Miles A, Clarkson CS, Mawejje HD, Wilding CS, Halfon MS, Asma H, Heinz E, Donnelly MJ. Mechanisms of transcriptional regulation in Anopheles gambiae revealed by allele specific expression. bioRxiv 2023:2023.11.22.568226. [PMID: 38045426 PMCID: PMC10690255 DOI: 10.1101/2023.11.22.568226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Malaria control relies on insecticides targeting the mosquito vector, but this is increasingly compromised by insecticide resistance, which can be achieved by elevated expression of detoxifying enzymes that metabolize the insecticide. In diploid organisms, gene expression is regulated both in cis, by regulatory sequences on the same chromosome, and by trans acting factors, affecting both alleles equally. Differing levels of transcription can be caused by mutations in cis-regulatory modules (CRM), but few of these have been identified in mosquitoes. We crossed bendiocarb resistant and susceptible Anopheles gambiae strains to identify cis-regulated genes that might be responsible for the resistant phenotype using RNAseq, and cis-regulatory module sequences controlling gene expression in insecticide resistance relevant tissues were predicted using machine learning. We found 115 genes showing allele specific expression in hybrids of insecticide susceptible and resistant strains, suggesting cis regulation is an important mechanism of gene expression regulation in Anopheles gambiae. The genes showing allele specific expression included a higher proportion of Anopheles specific genes on average younger than genes those with balanced allelic expression.
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Affiliation(s)
- Naomi A Dyer
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Eric R Lucas
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Sanjay C Nagi
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Daniel P McDermott
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Jon H Brenas
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Alistair Miles
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Chris S Clarkson
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Henry D Mawejje
- Infectious Diseases Research Collaboration (IDRC), Plot 2C Nakasero Hill Road, P.O.Box 7475, Kampala, Uganda
| | - Craig S Wilding
- School of Biological and Environmental Sciences, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - Marc S Halfon
- Department of Biochemistry, Jacobs School of Medicine & Biomedical Sciences, University at Buffalo-State University of New York, 955 Main Street, Buffalo, New York 14203, USA
| | - Hasiba Asma
- Department of Biochemistry, Jacobs School of Medicine & Biomedical Sciences, University at Buffalo-State University of New York, 955 Main Street, Buffalo, New York 14203, USA
| | - Eva Heinz
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
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7
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Manole C, Skinner LJ, Donnelly MJ. Surgical outcomes for cutaneous squamous cell carcinoma of the auricle. World J Otorhinolaryngol Head Neck Surg 2023; 9:295-301. [PMID: 38059142 PMCID: PMC10696274 DOI: 10.1002/wjo2.137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 07/15/2023] [Accepted: 08/08/2023] [Indexed: 12/08/2023] Open
Abstract
Background Cutaneous squamous cell carcinoma (CSCC) on the auricle is believed to carry a higher risk of metastatic spread. The rates of lymphatic metastasis reported in the literature have varied widely. There are no established prognostic criteria to determine which of these tumors are higher risk and warrant prophylactic treatment of the associated lymphatic basins. Objective To retrospectively evaluate outcomes after surgical treatment of auricular CSCC in our department, examining excision completeness, tumor recurrence, and lymphatic metastasis. Secondarily, to identify factors associated with lymphatic metastasis. Methods One hundred and thirty-eight consecutive cases of auricular SCC were excised from 126 patients in our department over a 7-year period (January 2012-December 2018). Data were retrospectively collected on patient characteristics, tumor histology, surgical procedures, and follow-up. Results Incomplete initial excision occurred in 17 cases (12.32%). Six patients (4.76%) had a local recurrence. Lymphatic metastasis occurred in eight patients (6.35%), on average within 10.25 months after primary excision. Six patients with metastasis died during follow-up, with a mean survival of 10.2 months. Older age was associated with lymphatic metastasis (P = 0.0267). Other factors, including tumor recurrence, size, grade, cartilage invasion, and positive margins, were evaluated and not significantly associated with metastasis. Conclusion In this study, the metastatic rate of auricular SCC was 6.35%, which is within the previously reported ranges. No histological prognostic factors were identified in this study, which may be due to our limited sample size. In the absence of established prognostic criteria, decisions regarding prophylactic treatment should be made on an individual basis with multidisciplinary support.
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Affiliation(s)
- Constantin Manole
- Department of Otolaryngology/Head and Neck SurgeryUniversity Hospital WaterfordWaterfordRepublic of Ireland
| | - Liam J. Skinner
- Consultant in Otolaryngology/Head and Neck SurgeryUniversity Hospital WaterfordWaterfordRepublic of Ireland
| | - Martin J. Donnelly
- Consultant in Otolaryngology/Head and Neck SurgeryUniversity Hospital WaterfordWaterfordRepublic of Ireland
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Omondi S, Kosgei J, Musula G, Muchoki M, Abong'o B, Agumba S, Ogwang C, McDermott DP, Donnelly MJ, Staedke SG, Schultz J, Gutman JR, Gimnig JE, Ochomo E. Late morning biting behaviour of Anopheles funestus is a risk factor for transmission in schools in Siaya, western Kenya. Malar J 2023; 22:366. [PMID: 38037026 PMCID: PMC10691009 DOI: 10.1186/s12936-023-04806-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 11/23/2023] [Indexed: 12/02/2023] Open
Abstract
BACKGROUND Children in Kenya spend a substantial amount of time at school, including at dawn and dusk when mosquitoes are active. With changing vector behaviour towards early morning biting, it is important to determine whether there is an additional risk of transmission in schools. This study sought to understand whether late morning biting by Anopheles funestus, previously documented in households in western Kenya, was replicated in schools. METHODS From the 4th to the 6th of August 2023, human landing collections were conducted hourly in four schools in Alego Usonga sub-County, Siaya County. The collections were conducted in and outside five classrooms in each school and ran for 17 h, starting at 18:00 until 11:00 h the next morning. RESULTS Anopheles funestus was the predominant species collected, forming 93.2% (N = 727) of the entire collection, with peak landing between 06:00 and 07:00 h and continuing until 11:00 h. More than half of the collected An. funestus were either fed or gravid, potentially indicative of multiple bloodmeals within each gonotrophic cycle, and had a sporozoite rate of 2.05%. CONCLUSION School children spend up to 10 h of their daytime in schools, reporting between 06:00 and 07:00 h and staying in school until as late as 17:00 h, meaning that they receive potentially infectious mosquito bites during the morning hours in these settings. There is a need to consider vector control approaches targeting schools and other peridomestic spaces in the morning hours when An. funestus is active.
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Affiliation(s)
- Seline Omondi
- Entomology Section, Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Jackline Kosgei
- Entomology Section, Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - George Musula
- Entomology Section, Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Margaret Muchoki
- Entomology Section, Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Bernard Abong'o
- Entomology Section, Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Silas Agumba
- Entomology Section, Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Caroline Ogwang
- Entomology Section, Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Daniel P McDermott
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Sarah G Staedke
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Jonathan Schultz
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Julie R Gutman
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - John E Gimnig
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Eric Ochomo
- Entomology Section, Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya.
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Lucas ER, Nagi SC, Egyir-Yawson A, Essandoh J, Dadzie S, Chabi J, Djogbénou LS, Medjigbodo AA, Edi CV, Kétoh GK, Koudou BG, Van't Hof AE, Rippon EJ, Pipini D, Harding NJ, Dyer NA, Cerdeira LT, Clarkson CS, Kwiatkowski DP, Miles A, Donnelly MJ, Weetman D. Genome-wide association studies reveal novel loci associated with pyrethroid and organophosphate resistance in Anopheles gambiae and Anopheles coluzzii. Nat Commun 2023; 14:4946. [PMID: 37587104 PMCID: PMC10432508 DOI: 10.1038/s41467-023-40693-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 08/03/2023] [Indexed: 08/18/2023] Open
Abstract
Resistance to insecticides in Anopheles mosquitoes threatens the effectiveness of malaria control, but the genetics of resistance are only partially understood. We performed a large scale multi-country genome-wide association study of resistance to two widely used insecticides: deltamethrin and pirimiphos-methyl, using sequencing data from An. gambiae and An. coluzzii from ten locations in West Africa. Resistance was highly multi-genic, multi-allelic and variable between populations. While the strongest and most consistent association with deltamethrin resistance came from Cyp6aa1, this was based on several independent copy number variants (CNVs) in An. coluzzii, and on a non-CNV haplotype in An. gambiae. For pirimiphos-methyl, signals included Ace1, cytochrome P450s, glutathione S-transferases and the nAChR target site of neonicotinoid insecticides. The regions around Cyp9k1 and the Tep family of immune genes showed evidence of cross-resistance to both insecticides. These locally-varying, multi-allelic patterns highlight the challenges involved in genomic monitoring of resistance, and may form the basis for improved surveillance methods.
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Affiliation(s)
- Eric R Lucas
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
| | - Sanjay C Nagi
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | | | - John Essandoh
- Department of Biomedical Sciences, University of Cape Coast, Cape Coast, Ghana
| | - Samuel Dadzie
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Joseph Chabi
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Luc S Djogbénou
- Tropical Infectious Diseases Research Centre (TIDRC), Université d'Abomey-Calavi (UAC), 01 B.P. 526, Cotonou, Benin
| | - Adandé A Medjigbodo
- Tropical Infectious Diseases Research Centre (TIDRC), Université d'Abomey-Calavi (UAC), 01 B.P. 526, Cotonou, Benin
| | - Constant V Edi
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01 BP 1303, Abidjan, Côte d'Ivoire
| | - Guillaume K Kétoh
- Laboratory of Ecology and Ecotoxicology, Department of Zoology, Faculty of Sciences, Université de Lomé, 01 B.P. 1515, Lomé, Togo
| | - Benjamin G Koudou
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01 BP 1303, Abidjan, Côte d'Ivoire
| | - Arjen E Van't Hof
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branišovská 31, 370 05, České Budějovice, Czech Republic
| | - Emily J Rippon
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Dimitra Pipini
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Nicholas J Harding
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Naomi A Dyer
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Louise T Cerdeira
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | | | | | - Alistair Miles
- Wellcome Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
- Wellcome Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK.
| | - David Weetman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
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10
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Lynd A, Gonahasa S, Staedke SG, Oruni A, Maiteki-Sebuguzi C, Hancock P, Knight E, Dorsey G, Opigo J, Yeka A, Katureebe A, Kyohere M, Hemingway J, Kamya MR, McDermott D, Lucas ER, Donnelly MJ. LLIN Evaluation in Uganda Project (LLINEUP) - Plasmodium infection prevalence and genotypic markers of insecticide resistance in Anopheles vectors from 48 districts of Uganda. medRxiv 2023:2023.07.31.23293323. [PMID: 37577716 PMCID: PMC10418296 DOI: 10.1101/2023.07.31.23293323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Background In 2017-2019, we conducted a large-scale, cluster-randomised trial (LLINEUP) to evaluate long-lasting insecticidal nets (LLINs) treated with a pyrethroid insecticide plus the synergist piperonyl butoxide (PBO LLINs), as compared to conventional, pyrethroid-only LLINs across 104 health sub-districts (HSDs) in Uganda. In LLINEUP, and similar trials in Tanzania, PBO LLINs were found to provide greater protection against malaria than conventional LLINs, reducing parasitaemia and vector density. In the LLINEUP trial, cross-sectional entomological surveys were carried out at baseline and then every 6 months for two years. In each survey, ten households per HSD were randomly selected for indoor household entomological collections. Results Overall, 5395 female Anopheles mosquitoes were collected from 5046 households. The proportion of mosquitoes infected with Plasmodium falciparum did not change significantly over time, while infection with non-falciparum malaria decreased in An. gambiae s.s, but not An. funestus. The frequency of genetic markers associated with pyrethroid resistance increased significantly over time, but the rate of change was not different between the two LLIN types. The knock-down resistance (kdr) mutation Vgsc-995S declined over time as Vgsc-995F, the alternative resistance mutation at this codon, increased. Vgsc-995F appears to be spreading into Uganda. Conclusions Distribution of LLINs in Uganda was associated with reductions in parasite prevalence and vector density, but the proportion of infective mosquitoes remained stable, suggesting that the potential for transmission persisted. The increased frequency of markers of pyrethroid resistance indicates that LLIN distribution favoured the evolution of resistance within local vectors and highlights the potential benefits of resistance management strategies.Trial registration:: This study is registered with ISRCTN, ISRCTN17516395. Registered 14 February 2017, http://www.isrctn.com/ISRCTN17516395.
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Affiliation(s)
- Amy Lynd
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Samuel Gonahasa
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Sarah G Staedke
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Ambrose Oruni
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | | | | | - Erin Knight
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Grant Dorsey
- University of California, San Francisco, San Francisco, CA 94110 USA
| | | | - Adoke Yeka
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Agaba Katureebe
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Mary Kyohere
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Janet Hemingway
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Moses R Kamya
- Makerere University College of Health Sciences
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Daniel McDermott
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Eric R Lucas
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Martin J Donnelly
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
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11
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Abong'o B, Stanton MC, Donnelly MJ, Ochomo E, Ter Kuile FO, Samuels AM, Kariuki S, Musula G, Oxborough R, Munga S, Torr SJ, Gimnig JE. Evaluation of community-based vector surveillance system for routine entomological monitoring under low malaria vector densities and high bed net coverage in western Kenya. Malar J 2023; 22:203. [PMID: 37400805 DOI: 10.1186/s12936-023-04629-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 06/20/2023] [Indexed: 07/05/2023] Open
Abstract
BACKGROUND Entomological surveillance is traditionally conducted by supervised teams of trained technicians. However, it is expensive and limiting in the number of sites visited. Surveillance through community-based collectors (CBC) may be more cost-effective and sustainable for longitudinal entomological monitoring. This study evaluated the efficiency of CBCs in monitoring mosquito densities compared to quality-assured sampling conducted by experienced entomology technicians. METHODS Entomological surveillance employing CBCs was conducted in eighteen clusters of villages in western Kenya using indoor and outdoor CDC light traps and indoor Prokopack aspiration. Sixty houses in each cluster were enrolled and sampled once every month. Collected mosquitoes were initially identified to the genus level by CBCs, preserved in 70% ethanol and transferred to the laboratory every 2 weeks. Parallel, collections by experienced entomology field technicians were conducted monthly by indoor and outdoor CDC light traps and indoor Prokopack aspiration and served as a quality assurance of the CBCs. RESULTS Per collection, the CBCs collected 80% fewer Anopheles gambiae sensu lato (s.l.) [RR = 0.2; (95% CI 0.14-0.27)] and Anopheles coustani [RR = 0.2; (95% CI 0.06-0.53)] and 90% fewer Anopheles funestus [RR = 0.1; (95% CI 0.08-0.19)] by CDC light traps compared to the quality assured (QA) entomology teams. Significant positive correlations were however observed between the monthly collections by CBCs and QA teams for both An. gambiae and An. funestus. In paired identifications of pooled mosquitoes, the CBCs identified 4.3 times more Anopheles compared to experienced technicians. The cost per person-night was lower in the community-based sampling at $9.1 compared to $89.3 by QA per collection effort. CONCLUSION Unsupervised community-based mosquito surveillance collected substantially fewer mosquitoes per trap-night compared to quality-assured collection by experienced field teams, while consistently overestimating the number of Anopheles mosquitoes during identification. However, the numbers collected were significantly correlated between the CBCs and the QA teams suggesting that trends observed by CBCs and QA teams were similar. Further studies are needed to evaluate whether adopting low-cost, devolved supervision with spot checks, coupled with remedial training of the CBCs, can improve community-based collections to be considered a cost-effective alternative to surveillance conducted by experienced entomological technicians.
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Affiliation(s)
- Bernard Abong'o
- Centre for Global Health Research, Kenya Medical Research Institute, PO Box 1578, 40100, Kisumu, Kenya.
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
| | - Michelle C Stanton
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Martin J Donnelly
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Eric Ochomo
- Centre for Global Health Research, Kenya Medical Research Institute, PO Box 1578, 40100, Kisumu, Kenya
| | - Feiko O Ter Kuile
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Aaron M Samuels
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Kisumu, Kenya
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Simon Kariuki
- Centre for Global Health Research, Kenya Medical Research Institute, PO Box 1578, 40100, Kisumu, Kenya
| | - George Musula
- Centre for Global Health Research, Kenya Medical Research Institute, PO Box 1578, 40100, Kisumu, Kenya
| | - Richard Oxborough
- PMI VectorLink Project, Abt Associates Inc, 6130 Executive Blvd, Rockville, MD, 20852, USA
| | - Stephen Munga
- Centre for Global Health Research, Kenya Medical Research Institute, PO Box 1578, 40100, Kisumu, Kenya
| | - Steve J Torr
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - John E Gimnig
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
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12
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Sy O, Sarr PC, Assogba BS, Nourdine MA, Ndiaye A, Konaté L, Faye O, Donnelly MJ, Gaye O, Weetman D, Niang EA. Residual malaria transmission and the role of Anopheles arabiensis and Anopheles melas in central Senegal. J Med Entomol 2023; 60:546-553. [PMID: 36932704 PMCID: PMC10179433 DOI: 10.1093/jme/tjad020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 01/18/2023] [Accepted: 02/06/2023] [Indexed: 05/13/2023]
Abstract
Understanding the behavior and ecology of local malaria vectors is essential for the effectiveness of the commonly used vector-targeted malaria control tools in areas of low malaria transmission. This study was conducted to determine species composition, biting behavior and infectivity of the major Anopheles vectors of Plasmodium falciparum in low transmission settings in central Senegal. Adult mosquitoes were collected using human landing catches during 2 consecutive nights and Pyrethrum Spray Catches in 30-40 randomly selected rooms, from July 2017 to December 2018 in 3 villages. Anopheline mosquitoes were morphologically identified using conventional keys; their reproductive status assessed by ovary dissections, and a sub-sample of Anopheles gambiae s.l. were identified to species level using polymerase chain reaction (PCR). Plasmodium sporozoite infections were detected using real-time quantitative PCR. During this study 3684 Anopheles were collected of which 97% were An. gambiae s.l., 0.6% were Anopheles funestus, and 2.4% were Anopheles pharoensis. Molecular identification of 1,877 An. gambiae s.l. revealed a predominance of Anopheles arabiensis (68.7%), followed by Anopheles melas (28.8%), and Anopheles coluzzii (2.1%). The overall human-biting rate of An. gambiae s.l. was highest in the inland site of Keur Martin with 4.92 bites per person per night, while it was similar in the deltaic site, Diofior (0.51) and the coastal site, Mbine Coly (0.67). Parity rates were similar in An. arabiensis (45%) and An. melas (42%). Sporozoite infections were detected in both An. arabiensis and An. melas with the respective infection rates of 1.39% (N = 8) and 0.41% (N = 1). Results suggest that low residual malaria in central Senegal is transmitted by An. arabiensis and An. melas. Consequently, both vectors will need to be targeted as part of malaria elimination efforts in this area of Senegal.
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Affiliation(s)
- Ousmane Sy
- Laboratoire d'Écologie Vectorielle et Parasitaire, Faculté des Sciences et Techniques, Université Cheikh Anta DIOP Dakar/Sénégal
- Laboratory of Medical Parasitology (MARCAD program) Faculty of Medicine, Pharmacy and Odontostomatology of Cheikh Anta DIOP University of Dakar/Senegal
| | - Pape C Sarr
- Laboratoire d'Écologie Vectorielle et Parasitaire, Faculté des Sciences et Techniques, Université Cheikh Anta DIOP Dakar/Sénégal
- Laboratory of Medical Parasitology (MARCAD program) Faculty of Medicine, Pharmacy and Odontostomatology of Cheikh Anta DIOP University of Dakar/Senegal
| | - Benoit S Assogba
- Disease Control and Elimination Theme, Medical Research Council Unit, The Gambia at the London School of Hygiene and Tropical Medicine, Banjul P.O. Box 273, The Gambia
| | - Mouhamed A Nourdine
- Laboratoire d'Écologie Vectorielle et Parasitaire, Faculté des Sciences et Techniques, Université Cheikh Anta DIOP Dakar/Sénégal
- Laboratory of Medical Parasitology (MARCAD program) Faculty of Medicine, Pharmacy and Odontostomatology of Cheikh Anta DIOP University of Dakar/Senegal
| | - Assane Ndiaye
- Laboratoire d'Écologie Vectorielle et Parasitaire, Faculté des Sciences et Techniques, Université Cheikh Anta DIOP Dakar/Sénégal
| | - Lassana Konaté
- Laboratoire d'Écologie Vectorielle et Parasitaire, Faculté des Sciences et Techniques, Université Cheikh Anta DIOP Dakar/Sénégal
| | - Ousmane Faye
- Laboratoire d'Écologie Vectorielle et Parasitaire, Faculté des Sciences et Techniques, Université Cheikh Anta DIOP Dakar/Sénégal
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom
| | - Oumar Gaye
- Laboratory of Medical Parasitology (MARCAD program) Faculty of Medicine, Pharmacy and Odontostomatology of Cheikh Anta DIOP University of Dakar/Senegal
| | - David Weetman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom
| | - Elhadji A Niang
- Laboratoire d'Écologie Vectorielle et Parasitaire, Faculté des Sciences et Techniques, Université Cheikh Anta DIOP Dakar/Sénégal
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13
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Nagi SC, Oruni A, Weetman D, Donnelly MJ. RNA-Seq-Pop: Exploiting the sequence in RNA sequencing-A Snakemake workflow reveals patterns of insecticide resistance in the malaria vector Anopheles gambiae. Mol Ecol Resour 2023; 23:946-961. [PMID: 36695302 PMCID: PMC10568660 DOI: 10.1111/1755-0998.13759] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 11/12/2022] [Accepted: 01/06/2023] [Indexed: 01/26/2023]
Abstract
We provide a reproducible and scalable Snakemake workflow, called RNA-Seq-Pop, which provides end-to-end analysis of RNA sequencing data sets. The workflow allows the user to perform quality control, perform differential expression analyses and call genomic variants. Additional options include the calculation of allele frequencies of variants of interest, summaries of genetic variation and population structure, and genome-wide selection scans, together with clear visualizations. RNA-Seq-Pop is applicable to any organism, and we demonstrate the utility of the workflow by investigating pyrethroid resistance in selected strains of the major malaria mosquito, Anopheles gambiae. The workflow provides additional modules specifically for An. gambiae, including estimating recent ancestry and determining the karyotype of common chromosomal inversions. The Busia laboratory colony used for selections was collected in Busia, Uganda, in November 2018. We performed a comparative analysis of three groups: a parental G24 Busia strain; its deltamethrin-selected G28 offspring; and the susceptible reference strain Kisumu. Measures of genetic diversity reveal patterns consistent with that of laboratory colonization and selection, with the parental Busia strain exhibiting the highest nucleotide diversity, followed by the selected Busia offspring, and finally, Kisumu. Differential expression and variant analyses reveal that the selected Busia colony exhibits a number of distinct mechanisms of pyrethroid resistance, including the Vgsc-995S target-site mutation, upregulation of SAP genes, P450s and a cluster of carboxylesterases. During deltamethrin selections, the 2La chromosomal inversion rose in frequency (from 33% to 86%), supporting a previous link with pyrethroid resistance. RNA-Seq-Pop is hosted at: github.com/sanjaynagi/rna-seq-pop. We anticipate that the workflow will provide a useful tool to facilitate reproducible, transcriptomic studies in An. gambiae and other taxa.
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Affiliation(s)
- Sanjay C. Nagi
- Department of Vector BiologyLiverpool School of Tropical MedicineLiverpoolUK
| | | | - David Weetman
- Department of Vector BiologyLiverpool School of Tropical MedicineLiverpoolUK
| | - Martin J. Donnelly
- Department of Vector BiologyLiverpool School of Tropical MedicineLiverpoolUK
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14
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Kouamé RM, Lynd A, Kouamé JK, Vavassori L, Abo K, Donnelly MJ, Edi C, Lucas E. Widespread occurrence of copy number variants and fixation of pyrethroid target site resistance in Anopheles gambiae ( s.l.) from southern Côte d'Ivoire. Curr Res Parasitol Vector Borne Dis 2023; 3:100117. [PMID: 36970448 PMCID: PMC10031352 DOI: 10.1016/j.crpvbd.2023.100117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 02/09/2023] [Accepted: 02/21/2023] [Indexed: 03/07/2023]
Abstract
Resistance to pyrethroid and organophosphate insecticides in the malaria vector Anopheles gambiae (s.l.) is conferred by a variety of genetic mutations, including single nucleotide polymorphisms (SNPs) and copy number variants (CNVs). Knowledge of the distribution of these mutations in mosquito populations is a prerequisite for establishing better strategies for their management. In this study, a total of 755 Anopheles gambiae (s.l.) from southern Côte d'Ivoire were exposed to deltamethrin or pirimiphos-methyl insecticides and were screened to assess the distribution of SNPs and CNVs known or believed to confer resistance to one or other of the insecticide classes. Most individuals from the An. gambiae (s.l.) complex were identified by molecular tests as Anopheles coluzzii. Survival to deltamethrin (from 94% to 97%) was higher than to pirimiphos-methyl (from 10% to 49%). In An. gambiae (s.s.), the SNP in the Voltage Gated Sodium Channel (Vgsc) at the 995F locus (Vgsc-995F) was fixed, while other target site mutations were rare or absent (Vgsc-402L: 0%; Vgsc-1570Y: 0%, Acetylcholinesterase Acel-280S: 14%). In An. coluzzii, Vgsc-995F was the target site SNP found at highest frequency (65%) followed by other target site mutations (Vgsc-402L: 36%; Vgsc-1570Y: 0.33%; Acel-280S: 45%). The Vgsc-995S SNP was not present. The presence of the Ace1-280S SNP was found to be significantly linked to the presence of the Ace1-CNV, Ace1_AgDup. Significant association was found between the presence of the Ace1_AgDup and pirimiphos-methyl resistance in An. gambiae (s.s.) but not in An. coluzzii. The deletion Ace1_Del97 was found in one specimen of An. gambiae (s.s.). Four CNVs in the Cyp6aa/Cyp6p gene cluster, which contains genes of known importance for resistance, were detected in An. coluzzii, the most frequent being Dup 7 (42%) and Dup 14 (26%). While none of these individual CNV alleles were significantly associated with resistance, copy number in the Cyp6aa gene region in general was associated with increased resistance to deltamethrin. Elevated expression of Cyp6p3 was nearly associated with deltamethrin resistance, although there was no association of resistance with copy number. Use of alternative insecticides and control methods to arrest resistance spread in An. coluzzii populations is merited.
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Affiliation(s)
- Ruth M.A. Kouamé
- Institut National Polytechnique Félix Houphouët Boigny, BP 1093, Yamoussoukro, Côte d’Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, 01 BP 1303 Abidjan 01, Côte d’Ivoire
| | - Amy Lynd
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Jackson K.I. Kouamé
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, 01 BP 1303 Abidjan 01, Côte d’Ivoire
- Université Nangui Abrogoua, 02 BP 801 Abidjan 02, Côte d’Ivoire
| | - Laura Vavassori
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, 01 BP 1303 Abidjan 01, Côte d’Ivoire
- Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Kouabénan Abo
- Institut National Polytechnique Félix Houphouët Boigny, BP 1093, Yamoussoukro, Côte d’Ivoire
| | - Martin J. Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Constant Edi
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, 01 BP 1303 Abidjan 01, Côte d’Ivoire
| | - Eric Lucas
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
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15
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Maiteki-Sebuguzi C, Gonahasa S, Kamya MR, Katureebe A, Bagala I, Lynd A, Mutungi P, Kigozi SP, Opigo J, Hemingway J, Dorsey G, Donnelly MJ, Staedke SG. Effect of long-lasting insecticidal nets with and without piperonyl butoxide on malaria indicators in Uganda (LLINEUP): final results of a cluster-randomised trial embedded in a national distribution campaign. Lancet Infect Dis 2023; 23:247-258. [PMID: 36174592 DOI: 10.1016/s1473-3099(22)00469-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 07/06/2022] [Accepted: 07/07/2022] [Indexed: 02/01/2023]
Abstract
BACKGROUND Long-lasting insecticidal nets (LLINs) are the foundation of malaria control but resistance of mosquito vectors to pyrethroids threatens their effectiveness. We embedded a cluster-randomised trial into Uganda's 2017-18 campaign to distribute LLINs. LLINs with piperonyl butoxide (PBO) reduced parasite prevalence more effectively than conventional LLINs (without PBO) for 18 months. Here, we report the final 25-month survey results. METHODS LLINEUP was a cluster-randomised trial conducted in 48 districts in eastern and western Uganda. 104 health subdistricts (clusters) without ongoing or planned indoor residual spraying with pirimiphos-methyl (Actellic, Basel, Switzerland) were eligible for inclusion in the trial. Clusters were randomly assigned to PBO LLINs (PermaNet 3.0 or Olyset Plus) and conventional LLINs (PermaNet 2.0 or Olyset Net) with proportionate randomisation using STATA version 14.2. LLINs were delivered from March 25, 2017, to March 18, 2018. Between April 23, 2019, and Sept 13, 2019, community surveys were conducted in 50 randomly selected households per cluster; ten households per cluster were randomly selected for entomology surveys. Mosquitoes were collected in the morning from indoor surfaces of households using Prokopack aspirators. Due to COVID-19 restrictions, only 90 of the 104 clusters were surveyed at 25 months. The primary outcome was parasite prevalence by microscopy in children aged 2-10 years, assessed in the as-treated population, determined using the results from the 6-month household survey on the type of LLINs received in each cluster. This trial is registered with ISRCTN, ISRCTN17516395, and is now completed. FINDINGS In the as-treated analysis, two clusters were excluded (no predominant LLIN received) and four were reassigned; 40 PBO LLIN clusters (30 PermaNet 3.0, ten Olyset Plus) and 48 non-PBO LLIN (36 PermaNet 2.0, 12 Olyset Net) were included. Parasite prevalence was 17·1% (506 of 2958 participants) in the PBO group and 19·8% (701 of 3534) in the non-PBO group (prevalence ratio adjusted for baseline 0·80 [95% CI 0·69-0·93], p=0·0048). Comparing within-treatment group parasite prevalence to baseline, parasite prevalence ratios were lower in the PBO groups at all timepoints, but the difference was greatest at 6 months (PBO LLINs parasite prevalence at baseline 28·8% [1001 of 3472, 95% CI 27·3-30·4] vs at 6 months 12·0% [361 of 3009, 10·9-13·2], prevalence ratio [PR] 0·43 [95% CI 0·36-0·52], p<0·0001; non-PBO LLINs parasite prevalence at baseline 25·4% [1015 of 4004, 24·0-26·7] vs 6 months 14·8% [526 of 3551, 13·7-16·0], PR 0·60 [0·54-0·68], p<0·0001) and 25 months (PBO LLINs parasite prevalence at 25 months 17·1% [506 of 2958, 15·8-18·5], PR 0·63 [95% CI 0·57-0·71], p<0·0001; non-PBO LLINs parasite prevalence at 25 months 19·8% [701 of 3534, 18·5-21·2], PR 0·79 [0·73-0·86], p<0·0001). INTERPRETATION In Uganda, PBO LLINs outperformed pyrethroid-only LLINs for 25 months. WHO concluded that PBO LLINs are more effective against malaria than non-PBO LLINs when resistance to pyrethroids is high and issued a conditional recommendation suggesting PBO LLINs should be deployed in areas of pyrethroid resistance. FUNDING The Against Malaria Foundation, UK Department for International Development, Innovative Vector Control Consortium, and Bill and Melinda Gates Foundation.
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Affiliation(s)
- Catherine Maiteki-Sebuguzi
- Infectious Diseases Research Collaboration, Kampala, Uganda; National Malaria Control Division, Ministry of Health, Kampala, Uganda
| | | | - Moses R Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda; Department of Medicine, Makerere University, Kampala, Uganda
| | | | - Irene Bagala
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Amy Lynd
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Peter Mutungi
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Simon P Kigozi
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Jimmy Opigo
- National Malaria Control Division, Ministry of Health, Kampala, Uganda
| | - Janet Hemingway
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Grant Dorsey
- Department of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK; Wellcome Sanger Institute, Hinxton, UK
| | - Sarah G Staedke
- Infectious Diseases Research Collaboration, Kampala, Uganda; Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, UK.
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16
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Lucas ER, Nagi SC, Egyir-Yawson A, Essandoh J, Dadzie S, Chabi J, Djogbénou LS, Medjigbodo AA, Edi CV, Ketoh GK, Koudou BG, Van't Hof AE, Rippon EJ, Pipini D, Harding NJ, Dyer NA, Cerdeira LT, Clarkson CS, Kwiatkowski DP, Miles A, Donnelly MJ, Weetman D. Genome-wide association studies reveal novel loci associated with pyrethroid and organophosphate resistance in Anopheles gambiae s.l. bioRxiv 2023:2023.01.13.523889. [PMID: 36712022 PMCID: PMC9882144 DOI: 10.1101/2023.01.13.523889] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Resistance to insecticides in Anopheles mosquitoes threatens the effectiveness of the most widespread tools currently used to control malaria. The genetic underpinnings of resistance are still only partially understood, with much of the variance in resistance phenotype left unexplained. We performed a multi-country large scale genome-wide association study of resistance to two insecticides widely used in malaria control: deltamethrin and pirimiphos-methyl. Using a bioassay methodology designed to maximise the phenotypic difference between resistant and susceptible samples, we sequenced 969 phenotyped female An. gambiae and An. coluzzii from ten locations across four countries in West Africa (Benin, Côte d'Ivoire, Ghana and Togo), identifying single nucleotide polymorphisms (SNPs) and copy number variants (CNVs) segregating in the populations. The patterns of resistance association were highly multiallelic and variable between populations, with different genomic regions contributing to resistance, as well as different mutations within a given region. While the strongest and most consistent association with deltamethrin resistance came from the region around Cyp6aa1 , this resistance was based on a combination of several independent CNVs in An. coluzzii , and on a non-CNV bearing haplotype in An. gambiae . Further signals involved a range of cytochrome P450, mitochondrial, and immunity genes. Similarly, for pirimiphos-methyl, while the strongest signal came from the region of Ace1 , more widespread signals included cytochrome P450s, glutathione S-transferases, and a subunit of the nAChR target site of neonicotinoid insecticides. The regions around Cyp9k1 and the Tep family of immune genes were associated with resistance to both insecticide classes, suggesting possible cross-resistance mechanisms. These locally-varying, multigenic and multiallelic patterns highlight the challenges involved in genomic monitoring and surveillance of resistance, and form the basis for improvement of methods used to detect and predict resistance. Based on simulations of resistance variants, we recommend that yet larger scale studies, exceeding 500 phenotyped samples per population, are required to better identify associated genomic regions.
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Affiliation(s)
- Eric R Lucas
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Sanjay C Nagi
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | | | - John Essandoh
- Department of Biomedical Sciences, University of Cape Coast, Cape Coast, Ghana
| | - Sam Dadzie
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Joseph Chabi
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Luc S Djogbénou
- Tropical Infectious Diseases Research Centre (TIDRC), Université d'Abomey-Calavi (UAC), 01 B.P. 526, Cotonou, Benin
| | - Adandé A Medjigbodo
- Tropical Infectious Diseases Research Centre (TIDRC), Université d'Abomey-Calavi (UAC), 01 B.P. 526, Cotonou, Benin
| | - Constant V Edi
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01 BP 1303 Abidjan 01, Côte d'Ivoire
| | - Guillaume K Ketoh
- Laboratory of Ecology and Ecotoxicology, Department of Zoology, Faculty of Sciences, Université de Lomé, 01 B.P: 1515 Lomé 01, Togo
| | - Benjamin G Koudou
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01 BP 1303 Abidjan 01, Côte d'Ivoire
| | - Arjen E Van't Hof
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branišovská 31, 370 05 České Budějovice, Czech Republic
| | - Emily J Rippon
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Dimitra Pipini
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Nicholas J Harding
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
| | - Naomi A Dyer
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Louise T Cerdeira
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Chris S Clarkson
- Wellcome Sanger Institute, Hinxton, Cambridge CB10 1SA, United Kingdom
| | | | - Alistair Miles
- Wellcome Sanger Institute, Hinxton, Cambridge CB10 1SA, United Kingdom
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
- Wellcome Sanger Institute, Hinxton, Cambridge CB10 1SA, United Kingdom
| | - David Weetman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
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17
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Mawejje HD, Weetman D, Epstein A, Lynd A, Opigo J, Maiteki-Sebuguzi C, Lines J, Kamya MR, Rosenthal PJ, Donnelly MJ, Dorsey G, Staedke SG. Characterizing pyrethroid resistance and mechanisms in Anopheles gambiae ( s.s.) and Anopheles arabiensis from 11 districts in Uganda. Curr Res Parasitol Vector Borne Dis 2023; 3:100106. [PMID: 36590346 PMCID: PMC9798136 DOI: 10.1016/j.crpvbd.2022.100106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 11/09/2022] [Accepted: 12/01/2022] [Indexed: 12/14/2022]
Abstract
Insecticide resistance threatens recent progress on malaria control in Africa. To characterize pyrethroid resistance in Uganda, Anopheles gambiae (s.s.) and Anopheles arabiensis were analyzed from 11 sites with varied vector control strategies. Mosquito larvae were collected between May 2018 and December 2020. Sites were categorized as receiving no indoor-residual spraying ('no IRS', n = 3); where IRS was delivered from 2009 to 2014 and in 2017 and then discontinued ('IRS stopped', n = 4); and where IRS had been sustained since 2014 ('IRS active', n = 4). IRS included bendiocarb, pirimiphos methyl and clothianidin. All sites received long-lasting insecticidal nets (LLINs) in 2017. Adult mosquitoes were exposed to pyrethroids; with or without piperonyl butoxide (PBO). Anopheles gambiae (s.s.) and An. arabiensis were identified using PCR. Anopheles gambiae (s.s.) were genotyped for Vgsc-995S/F, Cyp6aa1, Cyp6p4-I236M, ZZB-TE, Cyp4j5-L43F and Coeae1d, while An. arabiensis were examined for Vgsc-1014S/F. Overall, 2753 An. gambiae (s.l.), including 1105 An. gambiae (s.s.) and 1648 An. arabiensis were evaluated. Species composition varied by site; only nine An. gambiae (s.s.) were collected from 'IRS active' sites, precluding species-specific comparisons. Overall, mortality following exposure to permethrin and deltamethrin was 18.8% (148/788) in An. gambiae (s.s.) and 74.6% (912/1222) in An. arabiensis. Mortality was significantly lower in An. gambiae (s.s.) than in An. arabiensis in 'no IRS' sites (permethrin: 16.1 vs 67.7%, P < 0.001; deltamethrin: 24.6 vs 83.7%, P < 0.001) and in 'IRS stopped' sites (permethrin: 11.3 vs 63.6%, P < 0.001; deltamethrin: 25.6 vs 88.9%, P < 0.001). When PBO was added, mortality increased for An. gambiae (s.s.) and An. arabiensis. Most An. gambiae (s.s.) had the Vgsc-995S/F mutation (95% frequency) and the Cyp6p4-I236M resistance allele (87%), while the frequency of Cyp4j5 and Coeae1d were lower (52% and 55%, respectively). Resistance to pyrethroids was widespread and higher in An. gambiae (s.s.). Where IRS was active, An. arabiensis dominated. Addition of PBO to pyrethroids increased mortality, supporting deployment of PBO LLINs. Further surveillance of insecticide resistance and assessment of associations between genotypic markers and phenotypic outcomes are needed to better understand mechanisms of pyrethroid resistance and to guide vector control.
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Affiliation(s)
- Henry Ddumba Mawejje
- Infectious Diseases Research Collaboration, Kampala, Uganda.,London School of Hygiene and Tropical Medicine, London, UK
| | - David Weetman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Adrienne Epstein
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Amy Lynd
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Jimmy Opigo
- National Malaria Control Division, Uganda Ministry of Health, Kampala, Uganda
| | - Catherine Maiteki-Sebuguzi
- Infectious Diseases Research Collaboration, Kampala, Uganda.,National Malaria Control Division, Uganda Ministry of Health, Kampala, Uganda
| | - Jo Lines
- London School of Hygiene and Tropical Medicine, London, UK
| | - Moses R Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda.,Department of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | | | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Grant Dorsey
- Department of Medicine, University of California, San Francisco, USA
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18
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Kouamé RMA, Guglielmo F, Abo K, Ouattara AF, Chabi J, Sedda L, Donnelly MJ, Edi C. Education and Socio-economic status are key factors influencing use of insecticides and malaria knowledge in rural farmers in Southern Côte d'Ivoire. BMC Public Health 2022; 22:2443. [PMID: 36577975 PMCID: PMC9795670 DOI: 10.1186/s12889-022-14446-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 10/25/2022] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Insecticides play a key role in rural farming; however, their over- or misuse has been linked with a negative impact on malaria vector control policies. This study was conducted amongst agricultural communities in Southern Côte d'Ivoire to identify which insecticides are used by local farmers and how it relates to the perception of farmers on malaria. Understanding the use of insecticides may help in designing awareness programme on mosquito control and pesticides management. METHODS A questionnaire was administered to 1399 farming households across ten villages. Farmers were interviewed on their education, farming practices (e.g. crops cultivated, insecticides use), perception of malaria, and the different domestic strategies of mosquito control they use. Based on some pre-defined household assets, the socioeconomic status (SES) of each household was estimated. Statistical associations were calculated between different variables, showing significant risk factors. RESULTS The educational level of farmers was significantly associated with their SES (p < 0.0001). Most of the householders (88.82%) identified mosquitoes as the principal cause of malaria, with good knowledge of malaria resulting as positively related to high educational level (OR = 2.04; 95%CI: 1.35, 3.10). The use of indoor chemical compounds was strongly associated to the SES of the households, their education level, their use of ITNs and insecticide in agricultural (p < 0.0001). Indoor application of pyrethroid insecticides was found to be widespread among farmers as well as the use of such insecticide for crops protection. CONCLUSION Our study shows that the education level remains the key factor influencing the use of insecticides by farmers and their awareness of malaria control. We suggest that better communication tailored to education level and including SES, controlled availability and access to chemical products, should be considered when designing campaigns on use of pesticides and vector borne disease control for local communities.
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Affiliation(s)
- Ruth M A Kouamé
- Institut National Polytechnique Félix Houphouët Boigny, BP 1093, Yamoussoukro, Côte d'Ivoire.,Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01 BP 1303, Abidjan, Côte d'Ivoire
| | - Federica Guglielmo
- Liverpool School of Tropical Medicine, Vector Biology Department, Pembroke Place, Liverpool, L3 5QA, United Kingdom
| | - Kouabénan Abo
- Institut National Polytechnique Félix Houphouët Boigny, BP 1093, Yamoussoukro, Côte d'Ivoire
| | - Allassane F Ouattara
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01 BP 1303, Abidjan, Côte d'Ivoire.,Université Nangui Abrogoua, 02 BP 801, Abidjan, Côte d'Ivoire
| | - Joseph Chabi
- Noguchi Memorial Institute for Medical Research, Accra, Ghana
| | - Luigi Sedda
- Lancaster Ecology and Epidemiology Group, Lancaster Medical School, Lancaster University, Furness Building, Lancaster, LA1 4YG, United Kingdom
| | - Martin J Donnelly
- Liverpool School of Tropical Medicine, Vector Biology Department, Pembroke Place, Liverpool, L3 5QA, United Kingdom
| | - Constant Edi
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01 BP 1303, Abidjan, Côte d'Ivoire.
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19
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Nankabirwa JI, Rek J, Arinaitwe E, Namuganga JF, Nsobya SL, Asua V, Mawejje HD, Epstein A, Greenhouse B, Rodriguez-Barraquer I, Briggs J, Krezanoski PJ, Rosenthal PJ, Conrad M, Smith D, Staedke SG, Drakeley C, Bousema T, Andolina C, Donnelly MJ, Kamya MR, Dorsey G. East Africa International Center of Excellence for Malaria Research: Summary of Key Research Findings. Am J Trop Med Hyg 2022; 107:21-32. [PMID: 36228916 PMCID: PMC9662228 DOI: 10.4269/ajtmh.21-1285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 03/16/2022] [Indexed: 12/24/2022] Open
Abstract
The Program for Resistance, Immunology, Surveillance, and Modeling of Malaria (PRISM) has been conducting malaria research in Uganda since 2010 to improve the understanding of the disease and measure the impact of population-level control interventions in the country. Here, we will summarize key research findings from a series of studies addressing routine health facility-based surveillance, comprehensive cohort studies, studies of the molecular epidemiology, and transmission of malaria, evaluation of antimalarial drug efficacy, and resistance across the country, and assessments of insecticide resistance. Among our key findings are the following. First, we found that in historically high transmission areas of Uganda, a combination of universal distribution of long-lasting insecticidal-treated nets (LLINs) and sustained indoor residual spraying (IRS) of insecticides lowered the malaria burden greatly, but marked resurgences occurred if IRS was discontinued. Second, submicroscopic infections are common and key drivers of malaria transmission, especially in school-age children (5-15 years). Third, markers of drug resistance have changed over time, with new concerning emergence of markers predicting resistance to artemisinin antimalarials. Fourth, insecticide resistance monitoring has demonstrated high levels of resistance to pyrethroids, appreciable impact of the synergist piperonyl butoxide to pyrethroid susceptibility, emerging resistance to carbamates, and complete susceptibility of malaria vectors to organophosphates, which could have important implications for vector control interventions. Overall, PRISM has yielded a wealth of information informing researchers and policy-makers on the malaria burden and opportunities for improved malaria control and eventual elimination in Uganda. Continued studies concerning all the types of surveillance discussed above are ongoing.
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Affiliation(s)
- Joaniter I. Nankabirwa
- Infectious Diseases Research Collaboration, Kampala, Uganda
- Department of Medicine, Makerere University, College of Health Sciences, Kampala, Uganda
| | - John Rek
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | | | - Sam L. Nsobya
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Victor Asua
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | - Adrienne Epstein
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, California
| | - Bryan Greenhouse
- Department of Medicine, University of California San Francisco, San Francisco, California
| | | | - Jessica Briggs
- Department of Medicine, University of California San Francisco, San Francisco, California
| | - Paul J. Krezanoski
- Department of Medicine, University of California San Francisco, San Francisco, California
| | - Philip J. Rosenthal
- Department of Medicine, University of California San Francisco, San Francisco, California
| | - Melissa Conrad
- Department of Medicine, University of California San Francisco, San Francisco, California
| | - David Smith
- Institute for Health Metrics & Evaluation, University of Washington, Seattle, Washington
| | - Sarah G. Staedke
- Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Chris Drakeley
- Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Chiara Andolina
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Martin J. Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Moses R. Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda
- Department of Medicine, Makerere University, College of Health Sciences, Kampala, Uganda
| | - Grant Dorsey
- Department of Medicine, University of California San Francisco, San Francisco, California
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20
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Njoroge H, van't Hof A, Oruni A, Pipini D, Nagi S, Lynd A, Lucas ER, Tomlinson S, Grau‐Bove X, McDermott D, Wat'senga FT, Manzambi EZ, Agossa FR, Mokuba A, Irish S, Kabula B, Mbogo C, Bargul J, Paine MJI, Weetman D, Donnelly MJ. Identification of a rapidly-spreading triple mutant for high-level metabolic insecticide resistance in Anopheles gambiae provides a real-time molecular diagnostic for antimalarial intervention deployment. Mol Ecol 2022; 31:4307-4318. [PMID: 35775282 PMCID: PMC9424592 DOI: 10.1111/mec.16591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 06/07/2022] [Accepted: 06/27/2022] [Indexed: 12/01/2022]
Abstract
Studies of insecticide resistance provide insights into the capacity of populations to show rapid evolutionary responses to contemporary selection. Malaria control remains heavily dependent on pyrethroid insecticides, primarily in long lasting insecticidal nets (LLINs). Resistance in the major malaria vectors has increased in concert with the expansion of LLIN distributions. Identifying genetic mechanisms underlying high-level resistance is crucial for the development and deployment of resistance-breaking tools. Using the Anopheles gambiae 1000 genomes (Ag1000g) data we identified a very recent selective sweep in mosquitoes from Uganda which localized to a cluster of cytochrome P450 genes. Further interrogation revealed a haplotype involving a trio of mutations, a nonsynonymous point mutation in Cyp6p4 (I236M), an upstream insertion of a partial Zanzibar-like transposable element (TE) and a duplication of the Cyp6aa1 gene. The mutations appear to have originated recently in An. gambiae from the Kenya-Uganda border, with stepwise replacement of the double-mutant (Zanzibar-like TE and Cyp6p4-236 M) with the triple-mutant haplotype (including Cyp6aa1 duplication), which has spread into the Democratic Republic of Congo and Tanzania. The triple-mutant haplotype is strongly associated with increased expression of genes able to metabolize pyrethroids and is strongly predictive of resistance to pyrethroids most notably deltamethrin. Importantly, there was increased mortality in mosquitoes carrying the triple-mutation when exposed to nets cotreated with the synergist piperonyl butoxide (PBO). Frequencies of the triple-mutant haplotype remain spatially variable within countries, suggesting an effective marker system to guide deployment decisions for limited supplies of PBO-pyrethroid cotreated LLINs across African countries.
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Affiliation(s)
- Harun Njoroge
- Department of Vector BiologyLiverpool School of Tropical MedicineLiverpoolUK
- Kenya Medical Research Institute (KEMRI) Centre for Geographic Medicine CoastKEMRI‐Wellcome Trust Research ProgrammeKilifiKenya
| | - Arjen van't Hof
- Department of Vector BiologyLiverpool School of Tropical MedicineLiverpoolUK
| | - Ambrose Oruni
- Department of Vector BiologyLiverpool School of Tropical MedicineLiverpoolUK
- College of Veterinary MedicineAnimal Resources and Bio‐securityMakerere UniversityKampalaUganda
| | - Dimitra Pipini
- Department of Vector BiologyLiverpool School of Tropical MedicineLiverpoolUK
| | - Sanjay C. Nagi
- Department of Vector BiologyLiverpool School of Tropical MedicineLiverpoolUK
| | - Amy Lynd
- Department of Vector BiologyLiverpool School of Tropical MedicineLiverpoolUK
| | - Eric R. Lucas
- Department of Vector BiologyLiverpool School of Tropical MedicineLiverpoolUK
| | - Sean Tomlinson
- Department of Vector BiologyLiverpool School of Tropical MedicineLiverpoolUK
| | - Xavi Grau‐Bove
- Department of Vector BiologyLiverpool School of Tropical MedicineLiverpoolUK
| | - Daniel McDermott
- Department of Vector BiologyLiverpool School of Tropical MedicineLiverpoolUK
| | | | - Emile Z. Manzambi
- Institut National de Recherche BiomédicaleKinshasaDemocratic Republic of Congo
| | - Fiacre R. Agossa
- USAID President's Malaria Initiative, VectorLink Project, Abt AssociatesRockvilleMarylandUSA
| | - Arlette Mokuba
- USAID President's Malaria Initiative, VectorLink Project, Abt AssociatesRockvilleMarylandUSA
| | - Seth Irish
- U.S. President's Malaria Initiative and Centers for Disease Control and PreventionAtlantaGeorgiaUSA
| | - Bilali Kabula
- Amani Research CentreNational Institute for Medical ResearchTanzania
| | - Charles Mbogo
- Population Health UnitKEMRI‐Wellcome Trust Research ProgrammeNairobiKenya
- KEMRI‐Centre for Geographic Medicine Research CoastKilifiKenya
| | - Joel Bargul
- Department of BiochemistryJomo Kenyatta University of Agriculture and TechnologyJujaKenya
- The Animal Health DepartmentInternational Centre of Insect Physiology and EcologyNairobiKenya
| | - Mark J. I. Paine
- Department of Vector BiologyLiverpool School of Tropical MedicineLiverpoolUK
| | - David Weetman
- Department of Vector BiologyLiverpool School of Tropical MedicineLiverpoolUK
| | - Martin J. Donnelly
- Department of Vector BiologyLiverpool School of Tropical MedicineLiverpoolUK
- Parasites and Microbes ProgrammeWellcome Sanger InstituteCambridgeUK
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21
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Hancock PA, Lynd A, Wiebe A, Devine M, Essandoh J, Wat'senga F, Manzambi EZ, Agossa F, Donnelly MJ, Weetman D, Moyes CL. Modelling spatiotemporal trends in the frequency of genetic mutations conferring insecticide target-site resistance in African mosquito malaria vector species. BMC Biol 2022; 20:46. [PMID: 35164747 PMCID: PMC8845222 DOI: 10.1186/s12915-022-01242-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Accepted: 01/28/2022] [Indexed: 12/16/2022] Open
Abstract
Background Resistance in malaria vectors to pyrethroids, the most widely used class of insecticides for malaria vector control, threatens the continued efficacy of vector control tools. Target-site resistance is an important genetic resistance mechanism caused by mutations in the voltage-gated sodium channel (Vgsc) gene that encodes the pyrethroid target-site. Understanding the geographic distribution of target-site resistance, and temporal trends across different vector species, can inform strategic deployment of vector control tools. Results We develop a Bayesian statistical spatiotemporal model to interpret species-specific trends in the frequency of the most common resistance mutations, Vgsc-995S and Vgsc-995F, in three major malaria vector species Anopheles gambiae, An. coluzzii, and An. arabiensis over the period 2005–2017. The models are informed by 2418 observations of the frequency of each mutation in field sampled mosquitoes collected from 27 countries spanning western and eastern regions of Africa. For nine selected countries, we develop annual predictive maps which reveal geographically structured patterns of spread of each mutation at regional and continental scales. The results show associations, as well as stark differences, in spread dynamics of the two mutations across the three vector species. The coverage of ITNs was an influential predictor of Vgsc allele frequencies, with modelled relationships between ITN coverage and allele frequencies varying across species and geographic regions. We found that our mapped Vgsc allele frequencies are a significant partial predictor of phenotypic resistance to the pyrethroid deltamethrin in An. gambiae complex populations. Conclusions Our predictive maps show how spatiotemporal trends in insecticide target-site resistance mechanisms in African An. gambiae vary across individual vector species and geographic regions. Molecular surveillance of resistance mechanisms will help to predict resistance phenotypes and track their spread. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-022-01242-1.
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Affiliation(s)
| | - Amy Lynd
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L35QA, UK
| | | | - Maria Devine
- Big Data Institute, University of Oxford, Oxford, OX3 7LF, UK
| | - John Essandoh
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L35QA, UK
| | - Francis Wat'senga
- Institut National de Recherche Biomédicale, PO Box 1192, Kinshasa, Democratic Republic of Congo
| | - Emile Z Manzambi
- Institut National de Recherche Biomédicale, PO Box 1192, Kinshasa, Democratic Republic of Congo
| | - Fiacre Agossa
- USAID President's Malaria Initiative, VectorLink Project, Abt Associates, 6130 Executive Blvd 16, Rockville, MD, 20852, USA
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L35QA, UK
| | - David Weetman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L35QA, UK
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22
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Sherrard-Smith E, Winskill P, Hamlet A, Ngufor C, N'Guessan R, Guelbeogo MW, Sanou A, Nash RK, Hill A, Russell EL, Woodbridge M, Tungu P, Kont MD, Mclean T, Fornadel C, Richardson JH, Donnelly MJ, Staedke SG, Gonahasa S, Protopopoff N, Rowland M, Churcher TS. Optimising the deployment of vector control tools against malaria: a data-informed modelling study. Lancet Planet Health 2022; 6:e100-e109. [PMID: 35065707 DOI: 10.1016/s2542-5196(21)00296-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 10/28/2021] [Accepted: 10/29/2021] [Indexed: 05/10/2023]
Abstract
BACKGROUND Concern that insecticide resistant mosquitoes are threatening malaria control has driven the development of new types of insecticide treated nets (ITNs) and indoor residual spraying (IRS) of insecticide. Malaria control programmes have a choice of vector control interventions although it is unclear which controls should be used to combat the disease. The study aimed at producing a framework to easily compare the public health impact and cost-effectiveness of different malaria prevention measures currently in widespread use. METHODS We used published data from experimental hut trials conducted across Africa to characterise the entomological effect of pyrethroid-only ITNs versus ITNs combining a pyrethroid insecticide with the synergist piperonyl butoxide (PBO). We use these estimates to parameterise a dynamic mathematical model of Plasmodium falciparum malaria which is validated for two sites by comparing simulated results to empirical data from randomised control trials (RCTs) in Tanzania and Uganda. We extrapolated model simulations for a series of potential scenarios likely across the sub-Saharan African region and include results in an online tool (Malaria INtervention Tool [MINT]) that aims to identify optimum vector control intervention packages for scenarios with varying budget, price, entomological and epidemiological factors. FINDINGS Our model indicates that switching from pyrethroid-only to pyrethroid-PBO ITNs could averted up to twice as many cases, although the additional benefit is highly variable and depends on the setting conditions. We project that annual delivery of long-lasting, non-pyrethroid IRS would prevent substantially more cases over 3-years, while pyrethroid-PBO ITNs tend to be the most cost-effective intervention per case averted. The model was able to predict prevalence and efficacy against prevalence in both RCTs for the intervention types tested. MINT is applicable to regions of sub-Saharan Africa with endemic malaria and provides users with a method of designing intervention packages given their setting and budget. INTERPRETATION The most cost-effective vector control package will vary locally. Models able to recreate results of RCTs can be used to extrapolate outcomes elsewhere to support evidence-based decision making for investment in vector control. FUNDING Medical Research Council, IVCC, Wellcome Trust. TRANSLATION For the French translation of the abstract see Supplementary Materials section.
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Affiliation(s)
- Ellie Sherrard-Smith
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, UK.
| | - Peter Winskill
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, UK
| | - Arran Hamlet
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, UK
| | - Corine Ngufor
- Centre de Recherches Entomologiques de Cotonou, Cotonou, Benin; London School of Hygiene and Tropical Medicine, London, UK
| | | | - Moussa W Guelbeogo
- Centre National de Recherche et de Formation sur le Paludisme, Burkina Faso
| | - Antoine Sanou
- Centre National de Recherche et de Formation sur le Paludisme, Burkina Faso
| | - Rebecca K Nash
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, UK
| | - Alexander Hill
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, UK
| | - Emma L Russell
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, UK
| | - Mark Woodbridge
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, UK
| | - Patrick Tungu
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Mara D Kont
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, UK
| | - Tom Mclean
- Innovative Vector Control Consortium, Liverpool, UK
| | | | | | | | - Sarah G Staedke
- London School of Hygiene and Tropical Medicine, London, UK; Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | | | - Mark Rowland
- London School of Hygiene and Tropical Medicine, London, UK
| | - Thomas S Churcher
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, UK
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23
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Mechan F, Katureebe A, Tuhaise V, Mugote M, Oruni A, Onyige I, Bumali K, Thornton J, Maxwell K, Kyohere M, Kamya MR, Mutungi P, Kigozi SP, Yeka A, Opigo J, Maiteki-Sebuguzi C, Gonahasa S, Hemingway J, Dorsey G, Reimer LJ, Staedke SG, Donnelly MJ, Lynd A. LLIN evaluation in Uganda project (LLINEUP): The fabric integrity, chemical content and bioefficacy of long-lasting insecticidal nets treated with and without piperonyl butoxide across two years of operational use in Uganda. Current Research in Parasitology & Vector-Borne Diseases 2022; 2:100092. [PMID: 35734077 PMCID: PMC9207544 DOI: 10.1016/j.crpvbd.2022.100092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/06/2022] [Accepted: 05/18/2022] [Indexed: 11/28/2022]
Abstract
Long-lasting insecticidal nets (LLINs) supplemented with the synergist piperonyl butoxide have been developed in response to growing pyrethroid resistance; however, their durability in the field remains poorly described. A pragmatic cluster-randomised trial was embedded into Ugandaʼs 2017–2018 LLIN distribution to compare the durability of LLINs with and without PBO. A total of 104 clusters (health sub-districts) were included with each receiving one of four LLIN products, two with pyrethroid + PBO (Olyset Plus and PermaNet 3.0) and two pyrethroid-only (Olyset Net and PermaNet 2.0). Nets were sampled at baseline, 12 and 25 months post-distribution to assess physical condition, chemical content, and bioefficacy. Physical condition was quantified using proportionate Hole Index and chemical content measured using high-performance liquid chromatography. Bioefficacy was assessed with three-minute World Health Organisation (WHO) Cone and Wireball assays using pyrethroid-resistant Anopheles gambiae, with 1-h knockdown and 24-h mortality recorded. There was no difference in physical durability between LLIN products assessed (P = 0.644). The pyrethroid content of all products remained relatively stable across time-points but PBO content declined by 55% (P < 0.001) and 58% (P < 0.001) for Olyset Plus and PermaNet 3.0 respectively. Both PBO LLINs were highly effective against pyrethroid-resistant mosquitoes when new, knocking down all mosquitoes. However, bioefficacy declined over time with Olyset Plus knocking down 45.72% (95% CI: 22.84–68.62%, P = 0.021) and Permanent 3.0 knocking down 78.57% (95% CI: 63.57–93.58%, P < 0.001) after 25 months. Here we demonstrate that both Olyset Plus and PermaNet 3.0 are as durable as their pyrethroid-only equivalents and had superior bioefficacy against pyrethroid-resistant An. gambiae. However, the superiority of PBO-LLINs decreased with operational use, correlating with a reduction in total PBO content. This decline in bioefficacy after just two years is concerning and there is an urgent need to assess the durability of PBO LLINs in other settings. Olyset Plus and PermaNet 3.0 nets effective against pyrethroid-resistant Anopheles gambiae when new. Killing effect of both nets halved after two years. Nets in ‘traditional’ thatched-roof housing at high risk of damage.
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Affiliation(s)
- Frank Mechan
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
- Corresponding author.
| | | | | | | | - Ambrose Oruni
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | | | | | - Jonathan Thornton
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Kilama Maxwell
- Department of Medicine, Makerere University, Kampala, Uganda
| | - Mary Kyohere
- Department of Medicine, Makerere University, Kampala, Uganda
| | - Moses R. Kamya
- Infectious Diseases Research Collaboration, Uganda
- Makerere University - Johns Hopkins University (MUJHU) Research Collaboration, Kampala, Uganda
| | | | | | - Adoke Yeka
- Infectious Diseases Research Collaboration, Uganda
| | - Jimmy Opigo
- National Malaria Control Division, Ministry of Health, Kampala, Uganda
| | | | | | - Janet Hemingway
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Grant Dorsey
- Department of Medicine, University of California, San Francisco, USA
| | - Lisa J. Reimer
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Sarah G. Staedke
- Infectious Diseases Research Collaboration, Uganda
- Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, UK
| | - Martin J. Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Amy Lynd
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
- Corresponding author.
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24
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Epstein A, Maiteki-Sebuguzi C, Namuganga JF, Nankabirwa JI, Gonahasa S, Opigo J, Staedke SG, Rutazaana D, Arinaitwe E, Kamya MR, Bhatt S, Rodríguez-Barraquer I, Greenhouse B, Donnelly MJ, Dorsey G. Resurgence of malaria in Uganda despite sustained indoor residual spraying and repeated long lasting insecticidal net distributions. PLOS Glob Public Health 2022; 2:e0000676. [PMID: 36962736 PMCID: PMC10022262 DOI: 10.1371/journal.pgph.0000676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Accepted: 07/27/2022] [Indexed: 11/19/2022]
Abstract
Five years of sustained indoor residual spraying (IRS) of insecticide from 2014 to 2019, first using a carbamate followed by an organophosphate, was associated with a marked reduction in the incidence of malaria in five districts of Uganda. We assessed changes in malaria incidence over an additional 21 months, corresponding to a change in IRS formulations using clothianidin with and without deltamethrin. Using enhanced health facility surveillance data, our objectives were to 1) estimate the impact of IRS on monthly malaria case counts at five surveillance sites over a 6.75 year period, and 2) compare monthly case counts at five facilities receiving IRS to ten facilities in neighboring districts not receiving IRS. For both objectives, we specified mixed effects negative binomial regression models with random intercepts for surveillance site adjusting for rainfall, season, care-seeking, and malaria diagnostic. Following the implementation of IRS, cases were 84% lower in years 4-5 (adjusted incidence rate ratio [aIRR] = 0.16, 95% CI 0.12-0.22), 43% lower in year 6 (aIRR = 0.57, 95% CI 0.44-0.74), and 39% higher in the first 9 months of year 7 (aIRR = 1.39, 95% CI 0.97-1.97) compared to pre-IRS levels. Cases were 67% lower in IRS sites than non-IRS sites in year 6 (aIRR = 0.33, 95% CI 0.17-0.63) but 38% higher in the first 9 months of year 7 (aIRR = 1.38, 95% CI 0.90-2.11). We observed a resurgence in malaria to pre-IRS levels despite sustained IRS. The timing of this resurgence corresponded to a change of active ingredient. Further research is needed to determine causality.
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Affiliation(s)
- Adrienne Epstein
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, California, United States of America
| | | | | | - Joaniter I Nankabirwa
- Infectious Diseases Research Collaboration, Kampala, Uganda
- College of Health Sciences, Makerere University, Kampala, Uganda
| | | | - Jimmy Opigo
- National Malaria Control Division, Ministry of Health, Kampala, Uganda
| | - Sarah G Staedke
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Damian Rutazaana
- National Malaria Control Division, Ministry of Health, Kampala, Uganda
| | | | - Moses R Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda
- College of Health Sciences, Makerere University, Kampala, Uganda
| | - Samir Bhatt
- Department of Infectious Disease Epidemiology, Imperial College, St Mary's Hospital, London, United Kingdom
- Department of Public Health, Section of Epidemiology, University of Copenhagen, Copenhagen, Denmark
| | - Isabel Rodríguez-Barraquer
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Bryan Greenhouse
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Grant Dorsey
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
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25
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Clarkson CS, Miles A, Harding NJ, O’Reilly AO, Weetman D, Kwiatkowski D, Donnelly MJ. The genetic architecture of target-site resistance to pyrethroid insecticides in the African malaria vectors Anopheles gambiae and Anopheles coluzzii. Mol Ecol 2021; 30:5303-5317. [PMID: 33590926 PMCID: PMC9019111 DOI: 10.1111/mec.15845] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 12/10/2020] [Accepted: 01/08/2021] [Indexed: 01/08/2023]
Abstract
Resistance to pyrethroid insecticides is a major concern for malaria vector control. Pyrethroids target the voltage-gated sodium channel (VGSC), an essential component of the mosquito nervous system. Substitutions in the amino acid sequence can induce a resistance phenotype. We use whole-genome sequence data from phase 2 of the Anopheles gambiae 1000 Genomes Project (Ag1000G) to provide a comprehensive account of genetic variation in the Vgsc gene across 13 African countries. In addition to known resistance alleles, we describe 20 other non-synonymous nucleotide substitutions at appreciable population frequency and map these variants onto a protein model to investigate the likelihood of pyrethroid resistance phenotypes. Thirteen of these novel alleles were found to occur almost exclusively on haplotypes carrying the known L995F kdr (knock-down resistance) allele and may enhance or compensate for the L995F resistance genotype. A novel mutation I1527T, adjacent to a predicted pyrethroid-binding site, was found in tight linkage with V402L substitutions, similar to allele combinations associated with resistance in other insect species. We also analysed genetic backgrounds carrying resistance alleles, to determine which alleles have experienced recent positive selection, and describe ten distinct haplotype groups carrying known kdr alleles. Five of these groups are observed in more than one country, in one case separated by over 3000 km, providing new information about the potential for the geographical spread of resistance. Our results demonstrate that the molecular basis of target-site pyrethroid resistance in malaria vectors is more complex than previously appreciated, and provide a foundation for the development of new genetic tools for insecticide resistance management.
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Affiliation(s)
| | - Alistair Miles
- Wellcome Sanger InstituteCambridgeUK
- Big Data InstituteLi Ka Shing Centre for Health Information and DiscoveryUniversity of OxfordOxfordUK
| | - Nicholas J. Harding
- Big Data InstituteLi Ka Shing Centre for Health Information and DiscoveryUniversity of OxfordOxfordUK
| | | | | | - Dominic Kwiatkowski
- Wellcome Sanger InstituteCambridgeUK
- Big Data InstituteLi Ka Shing Centre for Health Information and DiscoveryUniversity of OxfordOxfordUK
| | - Martin J. Donnelly
- Wellcome Sanger InstituteCambridgeUK
- Liverpool School of Tropical MedicineLiverpoolUK
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26
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Lucas ER, Darby AC, Torr SJ, Donnelly MJ. A gene expression panel for estimating age in males and females of the sleeping sickness vector Glossina morsitans. PLoS Negl Trop Dis 2021; 15:e0009797. [PMID: 34555037 PMCID: PMC8491940 DOI: 10.1371/journal.pntd.0009797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 10/05/2021] [Accepted: 09/08/2021] [Indexed: 12/02/2022] Open
Abstract
Many vector-borne diseases are controlled by methods that kill the insect vectors responsible for disease transmission. Recording the age structure of vector populations provides information on mortality rates and vectorial capacity, and should form part of the detailed monitoring that occurs in the wake of control programmes, yet tools for obtaining estimates of individual age remain limited. We investigate the potential of using markers of gene expression to predict age in tsetse flies, which are the vectors of deadly and economically damaging African trypanosomiases. We use RNAseq to identify candidate expression markers, and test these markers using qPCR in laboratory-reared Glossina morsitans morsitans of known age. Measuring the expression of six genes was sufficient to obtain a prediction of age with root mean squared error of less than 8 days, while just two genes were sufficient to classify flies into age categories of ≤15 and >15 days old. Further testing of these markers in field-caught samples and in other species will determine the accuracy of these markers in the field. Many insect-borne diseases are controlled by methods that kill the insects responsible for disease transmission. Estimating the age structure of populations of disease-transmitting insects provides information on mortality rates and on the capacity of the population to maintain disease transmission, and should form part of the detailed monitoring that occurs in the wake of control programmes, yet tools for obtaining estimates of individual age remain limited. We investigate the potential of using markers of gene expression to predict age in tsetse flies, which are the vectors of deadly and economically damaging African trypanosomiases, such as sleeping sickness. We use RNA sequencing to identify candidate genes, and test their accuracy in laboratory-reared tsetse flies of known age. Measuring the expression of six genes was sufficient to obtain a prediction of age with root mean squared error of less than 8 days, while just two genes were sufficient to classify flies into age categories of ≤15 and >15 days old. Further testing of these markers in field-caught samples and in other species will determine the accuracy of these markers in the field.
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Affiliation(s)
- Eric R. Lucas
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- * E-mail:
| | - Alistair C. Darby
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Stephen J. Torr
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Martin J. Donnelly
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Wellcome Sanger Institute, Cambridge, United Kingdom
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27
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Abong'o B, Gimnig JE, Longman B, Odongo T, Wekesa C, Webwile A, Oloo B, Nduta M, Muchoki M, Omoke D, Wacira D, Opondo K, Ochomo E, Munga S, Donnelly MJ, Oxborough RM. Comparison of four outdoor mosquito trapping methods as potential replacements for human landing catches in western Kenya. Parasit Vectors 2021; 14:320. [PMID: 34118973 PMCID: PMC8196510 DOI: 10.1186/s13071-021-04794-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 05/20/2021] [Indexed: 11/23/2022] Open
Abstract
Introduction Longitudinal monitoring of outdoor-biting malaria vector populations is becoming increasingly important in understanding the dynamics of residual malaria transmission. However, the human landing catch (HLC), the gold standard for measuring human biting rates indoors and outdoors, is costly and raises ethical concerns related to increased risk of infectious bites among collectors. Consequently, routine data on outdoor-feeding mosquito populations are usually limited because of the lack of a scalable tool with similar sensitivity to outdoor HLC. Methodology The Anopheles trapping sensitivity of four baited proxy outdoor trapping methods—Furvela tent trap (FTT), host decoy trap (HDT), mosquito electrocuting traps (MET) and outdoor CDC light traps (OLT)—was assessed relative to HLC in a 5 × 5 replicated Latin square conducted over 25 nights in two villages of western Kenya. Indoor CDC light trap (ILT) was run in one house in each of the compounds with outdoor traps, while additional non-Latin square indoor and outdoor HLC collections were performed in one of the study villages. Results The MET, FTT, HDT and OLT sampled approximately 4.67, 7.58, 5.69 and 1.98 times more An. arabiensis compared to HLC, respectively, in Kakola Ombaka. Only FTT was more sensitive relative to HLC in sampling An. funestus in Kakola Ombaka (RR = 5.59, 95% CI 2.49–12.55, P < 0.001) and Masogo (RR = 4.38, 95% CI 1.62–11.80, P = 0.004) and in sampling An. arabiensis in Masogo (RR = 5.37, 95% CI 2.17–13.24, P < 0.001). OLT sampled significantly higher numbers of An. coustani in Kakola Ombaka (RR = 3.03, 95% CI 1.65–5.56, P < 0.001) and Masogo (RR = 2.88, 95% CI 1.15–7.22, P = 0.02) compared to HLC. OLT, HLC and MET sampled mostly An. coustani, FTT had similar proportions of An. funestus and An. arabiensis, while HDT sampled predominantly An. arabiensis in both villages. FTT showed close correlation with ILT in vector abundance for all three species at both collection sites. Conclusion FTT and OLT are simple, easily scalable traps and are potential replacements for HLC in outdoor sampling of Anopheles mosquitoes. However, the FTT closely mirrored indoor CDC light trap in mosquito indices and therefore may be more of an indoor mimic than a true outdoor collection tool. HDT and MET show potential for sampling outdoor host-seeking mosquitoes. However, the traps as currently designed may not be feasible for large-scale, longitudinal entomological monitoring. Therefore, the baited outdoor CDC light trap may be the most appropriate tool currently available for assessment of outdoor-biting and malaria transmission risk. Graphic abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-021-04794-3.
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Affiliation(s)
- Bernard Abong'o
- Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578, Kisumu, Kenya. .,PMI VectorLink Project, Abt Associates Inc., Whitehouse, Milimani, Kisumu, Ojijo Oteko Road, P.O. Box 895-40123, Kisumu, Kenya.
| | - John E Gimnig
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Bradley Longman
- PMI VectorLink Project, Abt Associates Inc., Whitehouse, Milimani, Kisumu, Ojijo Oteko Road, P.O. Box 895-40123, Kisumu, Kenya
| | - Tobias Odongo
- PMI VectorLink Project, Abt Associates Inc., Whitehouse, Milimani, Kisumu, Ojijo Oteko Road, P.O. Box 895-40123, Kisumu, Kenya
| | - Celestine Wekesa
- PMI VectorLink Project, Abt Associates Inc., Whitehouse, Milimani, Kisumu, Ojijo Oteko Road, P.O. Box 895-40123, Kisumu, Kenya
| | - Amos Webwile
- PMI VectorLink Project, Abt Associates Inc., Whitehouse, Milimani, Kisumu, Ojijo Oteko Road, P.O. Box 895-40123, Kisumu, Kenya
| | - Benjamin Oloo
- PMI VectorLink Project, Abt Associates Inc., Whitehouse, Milimani, Kisumu, Ojijo Oteko Road, P.O. Box 895-40123, Kisumu, Kenya
| | - Mercy Nduta
- PMI VectorLink Project, Abt Associates Inc., Whitehouse, Milimani, Kisumu, Ojijo Oteko Road, P.O. Box 895-40123, Kisumu, Kenya
| | - Margaret Muchoki
- PMI VectorLink Project, Abt Associates Inc., Whitehouse, Milimani, Kisumu, Ojijo Oteko Road, P.O. Box 895-40123, Kisumu, Kenya
| | - Diana Omoke
- Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578, Kisumu, Kenya
| | - Daniel Wacira
- The United States President's Malaria Initiative (PMI), US Embassy Nairobi, United Nations Avenue, Nairobi, Kenya
| | - Kevin Opondo
- PMI VectorLink Project, Abt Associates Inc., Whitehouse, Milimani, Kisumu, Ojijo Oteko Road, P.O. Box 895-40123, Kisumu, Kenya
| | - Eric Ochomo
- Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578, Kisumu, Kenya
| | - Stephen Munga
- Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578, Kisumu, Kenya
| | - Martin J Donnelly
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Richard M Oxborough
- PMI VectorLink Project, Abt Associates Inc., 6130 Executive Blvd, Rockville, MD, 20852, USA
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Mawejje HD, Kilama M, Kigozi SP, Musiime AK, Kamya M, Lines J, Lindsay SW, Smith D, Dorsey G, Donnelly MJ, Staedke SG. Impact of seasonality and malaria control interventions on Anopheles density and species composition from three areas of Uganda with differing malaria endemicity. Malar J 2021; 20:138. [PMID: 33678166 PMCID: PMC7938603 DOI: 10.1186/s12936-021-03675-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 02/25/2021] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) are the malaria control interventions primarily responsible for reductions in transmission intensity across sub-Saharan Africa. These interventions, however, may have differential impact on Anopheles species composition and density. This study examined the changing pattern of Anopheles species in three areas of Uganda with markedly different transmission intensities and different levels of vector control. METHODS From October 2011 to June 2016 mosquitoes were collected monthly using CDC light traps from 100 randomly selected households in three areas: Walukuba (low transmission), Kihihi (moderate transmission) and Nagongera (high transmission). LLINs were distributed in November 2013 in Walukuba and Nagongera and in June 2014 in Kihihi. IRS was implemented only in Nagongera, with three rounds of bendiocarb delivered between December 2014 and June 2015. Mosquito species were identified morphologically and by PCR (Polymerase Chain Reaction). RESULTS In Walukuba, LLIN distribution was associated with a decline in Anopheles funestus vector density (0.07 vs 0.02 mosquitoes per house per night, density ratio [DR] 0.34, 95% CI: 0.18-0.65, p = 0.001), but not Anopheles gambiae sensu stricto (s.s.) nor Anopheles arabiensis. In Kihihi, over 98% of mosquitoes were An. gambiae s.s. and LLIN distribution was associated with a decline in An. gambiae s.s. vector density (4.00 vs 2.46, DR 0.68, 95% CI: 0.49-0.94, p = 0.02). In Nagongera, the combination of LLINs and multiple rounds of IRS was associated with almost complete elimination of An. gambiae s.s. (28.0 vs 0.17, DR 0.004, 95% CI: 0.002-0.009, p < 0.001), and An. funestus sensu lato (s.l.) (3.90 vs 0.006, DR 0.001, 95% CI: 0.0005-0.004, p < 0.001), with a less pronounced decline in An. arabiensis (9.18 vs 2.00, DR 0.15 95% CI: 0.07-0.33, p < 0.001). CONCLUSIONS LLIN distribution was associated with reductions in An. funestus s.l. in the lowest transmission site and An. gambiae s.s. in the moderate transmission site. In the highest transmission site, a combination of LLINs and multiple rounds of IRS was associated with the near collapse of An. gambiae s.s. and An. funestus s.l. Following IRS, An. arabiensis, a behaviourally resilient vector, became the predominant species, which may have implications for malaria vector control activities. Development of interventions targeted at outdoor biting remains a priority.
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Affiliation(s)
- Henry Ddumba Mawejje
- Infectious Diseases Research Collaboration, Kampala, Uganda. .,London School of Hygiene and Tropical Medicine, London, UK.
| | - Maxwell Kilama
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Simon P Kigozi
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Alex K Musiime
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Moses Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda.,Department of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Jo Lines
- London School of Hygiene and Tropical Medicine, London, UK
| | | | - David Smith
- Department of Health Metrics Sciences, University of Washington, Seattle, WA, USA
| | - Grant Dorsey
- Department of Medicine, University of California, San Francisco, USA
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place Liverpool, UK
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29
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Grau-Bové X, Lucas E, Pipini D, Rippon E, van ‘t Hof AE, Constant E, Dadzie S, Egyir-Yawson A, Essandoh J, Chabi J, Djogbénou L, Harding NJ, Miles A, Kwiatkowski D, Donnelly MJ, Weetman D. Resistance to pirimiphos-methyl in West African Anopheles is spreading via duplication and introgression of the Ace1 locus. PLoS Genet 2021; 17:e1009253. [PMID: 33476334 PMCID: PMC7853456 DOI: 10.1371/journal.pgen.1009253] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 02/02/2021] [Accepted: 11/03/2020] [Indexed: 12/30/2022] Open
Abstract
Vector population control using insecticides is a key element of current strategies to prevent malaria transmission in Africa. The introduction of effective insecticides, such as the organophosphate pirimiphos-methyl, is essential to overcome the recurrent emergence of resistance driven by the highly diverse Anopheles genomes. Here, we use a population genomic approach to investigate the basis of pirimiphos-methyl resistance in the major malaria vectors Anopheles gambiae and A. coluzzii. A combination of copy number variation and a single non-synonymous substitution in the acetylcholinesterase gene, Ace1, provides the key resistance diagnostic in an A. coluzzii population from Côte d'Ivoire that we used for sequence-based association mapping, with replication in other West African populations. The Ace1 substitution and duplications occur on a unique resistance haplotype that evolved in A. gambiae and introgressed into A. coluzzii, and is now common in West Africa primarily due to selection imposed by other organophosphate or carbamate insecticides. Our findings highlight the predictive value of this complex resistance haplotype for phenotypic resistance and clarify its evolutionary history, providing tools to for molecular surveillance of the current and future effectiveness of pirimiphos-methyl based interventions.
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Affiliation(s)
- Xavier Grau-Bové
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Eric Lucas
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Dimitra Pipini
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Emily Rippon
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Arjèn E. van ‘t Hof
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Edi Constant
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
| | - Samuel Dadzie
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | | | - John Essandoh
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Department of Biomedical Sciences, University of Cape Coast, Cape Coast, Ghana
| | - Joseph Chabi
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Luc Djogbénou
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Institut Régional de Santé Publique, Université d’Abomey-Calavi, Benin
| | - Nicholas J. Harding
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
| | - Alistair Miles
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
- Wellcome Sanger Institute, Hinxton, United Kingdom
| | - Dominic Kwiatkowski
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
- Wellcome Sanger Institute, Hinxton, United Kingdom
| | - Martin J. Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Wellcome Sanger Institute, Hinxton, United Kingdom
| | - David Weetman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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30
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Grau-Bové X, Tomlinson S, O’Reilly AO, Harding NJ, Miles A, Kwiatkowski D, Donnelly MJ, Weetman D. Evolution of the Insecticide Target Rdl in African Anopheles Is Driven by Interspecific and Interkaryotypic Introgression. Mol Biol Evol 2020; 37:2900-2917. [PMID: 32449755 PMCID: PMC7530614 DOI: 10.1093/molbev/msaa128] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The evolution of insecticide resistance mechanisms in natural populations of Anopheles malaria vectors is a major public health concern across Africa. Using genome sequence data, we study the evolution of resistance mutations in the resistance to dieldrin locus (Rdl), a GABA receptor targeted by several insecticides, but most notably by the long-discontinued cyclodiene, dieldrin. The two Rdl resistance mutations (296G and 296S) spread across West and Central African Anopheles via two independent hard selective sweeps that included likely compensatory nearby mutations, and were followed by a rare combination of introgression across species (from A. gambiae and A. arabiensis to A. coluzzii) and across nonconcordant karyotypes of the 2La chromosomal inversion. Rdl resistance evolved in the 1950s as the first known adaptation to a large-scale insecticide-based intervention, but the evolutionary lessons from this system highlight contemporary and future dangers for management strategies designed to combat development of resistance in malaria vectors.
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Affiliation(s)
- Xavier Grau-Bové
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Sean Tomlinson
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Health Informatics, Computing and Statistics, Lancaster University, Lancaster, United Kingdom
| | - Andrias O O’Reilly
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Nicholas J Harding
- Big Data Institute, University of Oxford, Li Ka Shing Centre for Health Information and Discovery, Oxford, United Kingdom
| | - Alistair Miles
- Big Data Institute, University of Oxford, Li Ka Shing Centre for Health Information and Discovery, Oxford, United Kingdom
- Wellcome Sanger Institute, Hinxton, United Kingdom
| | - Dominic Kwiatkowski
- Big Data Institute, University of Oxford, Li Ka Shing Centre for Health Information and Discovery, Oxford, United Kingdom
- Wellcome Sanger Institute, Hinxton, United Kingdom
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Wellcome Sanger Institute, Hinxton, United Kingdom
| | - David Weetman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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31
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Staedke SG, Gonahasa S, Dorsey G, Kamya MR, Maiteki-Sebuguzi C, Lynd A, Katureebe A, Kyohere M, Mutungi P, Kigozi SP, Opigo J, Hemingway J, Donnelly MJ. Effect of long-lasting insecticidal nets with and without piperonyl butoxide on malaria indicators in Uganda (LLINEUP): a pragmatic, cluster-randomised trial embedded in a national LLIN distribution campaign. Lancet 2020; 395:1292-1303. [PMID: 32305094 PMCID: PMC7181182 DOI: 10.1016/s0140-6736(20)30214-2] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 01/16/2020] [Accepted: 01/24/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND Long-lasting insecticidal nets (LLINs) are the primary malaria prevention tool, but their effectiveness is threatened by pyrethroid resistance. We embedded a pragmatic cluster-randomised trial into Uganda's national LLIN campaign to compare conventional LLINs with those containing piperonyl butoxide (PBO), a synergist that can partially restore pyrethroid susceptibility in mosquito vectors. METHODS 104 health sub-districts, from 48 districts in Uganda, were randomly assigned to LLINs with PBO (PermaNet 3.0 and Olyset Plus) and conventional LLINs (PermaNet 2.0 and Olyset Net) by proportionate randomisation using an iterative process. At baseline 6, 12, and 18 months after LLIN distribution, cross-sectional surveys were done in 50 randomly selected households per cluster (5200 per survey); a subset of ten households per cluster (1040 per survey) were randomly selected for entomological surveys. The primary outcome was parasite prevalence by microscopy in children aged 2-10 years, assessed in the as-treated population at 6, 12, and 18 months. This trial is registered with ISRCTN, ISRCTN17516395. FINDINGS LLINs were delivered to households from March 25, 2017, to March 18, 2018, 32 clusters were randomly assigned to PermaNet 3.0, 20 to Olyset Plus, 37 to PermaNet 2.0, and 15 to Olyset Net. In the as-treated analysis, three clusters were excluded because no dominant LLIN was received, and four clusters were reassigned, resulting in 49 PBO LLIN clusters (31 received PermaNet 3.0 and 18 received Olyset Plus) and 52 non-PBO LLIN clusters (39 received PermaNet 2.0 and 13 received Olyset Net). At 6 months, parasite prevalence was 11% (386/3614) in the PBO group compared with 15% (556/3844) in the non-PBO group (prevalence ratio [PR] adjusted for baseline values 0·74, 95% CI 0·62-0·87; p=0·0003). Parasite prevalence was similar at month 12 (11% vs 13%; PR 0·73, 95% CI 0·63-0·85; p=0·0001) and month 18 (12% vs 14%; PR 0·84, 95% CI 0·72-0·98; p=0·029). INTERPRETATION In Uganda, where pyrethroid resistance is high, PBO LLINs reduced parasite prevalence more effectively than did conventional LLINs for up to 18 months. This study provides evidence needed to support WHO's final recommendation on use of PBO LLINs. FUNDING The Against Malaria Foundation, UK Department for International Development, Innovative Vector Control Consortium, and Bill and Melinda Gates Foundation.
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Affiliation(s)
- Sarah G Staedke
- Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, UK; Infectious Diseases Research Collaboration, Kampala, Uganda.
| | | | - Grant Dorsey
- Department of Medicine, University of California, San Francisco, CA, USA
| | - Moses R Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda; Department of Medicine, Makerere University, Kampala, Uganda
| | | | - Amy Lynd
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | | | - Mary Kyohere
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Peter Mutungi
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Simon P Kigozi
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Jimmy Opigo
- National Malaria Control Division, Ministry of Health, Kampala, Uganda
| | - Janet Hemingway
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK; Wellcome Sanger Institute, Hinxton, UK
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32
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Abong'o B, Gimnig JE, Torr SJ, Longman B, Omoke D, Muchoki M, Ter Kuile F, Ochomo E, Munga S, Samuels AM, Njagi K, Maas J, Perry RT, Fornadel C, Donnelly MJ, Oxborough RM. Impact of indoor residual spraying with pirimiphos-methyl (Actellic 300CS) on entomological indicators of transmission and malaria case burden in Migori County, western Kenya. Sci Rep 2020; 10:4518. [PMID: 32161302 PMCID: PMC7066154 DOI: 10.1038/s41598-020-61350-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 02/25/2020] [Indexed: 11/16/2022] Open
Abstract
Indoor residual spraying (IRS) of insecticides is a major vector control strategy for malaria prevention. We evaluated the impact of a single round of IRS with the organophosphate, pirimiphos-methyl (Actellic 300CS), on entomological and parasitological parameters of malaria in Migori County, western Kenya in 2017, in an area where primary vectors are resistant to pyrethroids but susceptible to the IRS compound. Entomological monitoring was conducted by indoor CDC light trap, pyrethrum spray catches (PSC) and human landing collection (HLC) before and after IRS. The residual effect of the insecticide was assessed monthly by exposing susceptible An. gambiae s.s. Kisumu strain to sprayed surfaces in cone assays and measuring mortality at 24 hours. Malaria case burden data were extracted from laboratory records of four health facilities within the sprayed area and two adjacent unsprayed areas. IRS was associated with reductions in An. funestus numbers in the intervention areas compared to non-intervention areas by 88% with light traps (risk ratio [RR] 0.12, 95% CI 0.07-0.21, p < 0.001) and 93% with PSC collections (RR = 0.07, 0.03-0.17, p < 0.001). The corresponding reductions in the numbers of An. arabiensis collected by PSC were 69% in the intervention compared to the non-intervention areas (RR = 0.31, 0.14-0.68, p = 0.006), but there was no significant difference with light traps (RR = 0.45, 0.21-0.96, p = 0.05). Before IRS, An. funestus accounted for over 80% of Anopheles mosquitoes collected by light trap and PSC in all sites. After IRS, An. arabiensis accounted for 86% of Anopheles collected by PSC and 66% by CDC light trap in the sprayed sites while the proportion in non-intervention sites remained unchanged. No sporozoite infections were detected in intervention areas after IRS and biting rates by An. funestus were reduced to near zero. Anopheles funestus and An. arabiensis were fully susceptible to pirimiphos-methyl and resistant to pyrethroids. The residual effect of Actellic 300CS lasted ten months on mud and concrete walls. Malaria case counts among febrile patients within IRS areas was lower post- compared to pre-IRS by 44%, 65% and 47% in Rongo, Uriri and Nyatike health facilities respectively. A single application of IRS with Actellic 300CS in Migori County provided ten months protection and resulted in the near elimination of the primary malaria vector An. funestus and a corresponding reduction of malaria case count among out-patients. The impact was less on An. arabiensis, most likely due to their exophilic nature.
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Affiliation(s)
- Bernard Abong'o
- Abt Associates, PMI VectorLink Project, White House, Milimani, Ojijo Oteko Road, P.O. Box 895-40123, Kisumu, Kenya.
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
- Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578, Kisumu, Kenya.
| | - John E Gimnig
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Stephen J Torr
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Bradley Longman
- Abt Associates, PMI VectorLink Project, White House, Milimani, Ojijo Oteko Road, P.O. Box 895-40123, Kisumu, Kenya
| | - Diana Omoke
- Abt Associates, PMI VectorLink Project, White House, Milimani, Ojijo Oteko Road, P.O. Box 895-40123, Kisumu, Kenya
| | - Margaret Muchoki
- Abt Associates, PMI VectorLink Project, White House, Milimani, Ojijo Oteko Road, P.O. Box 895-40123, Kisumu, Kenya
| | - Feiko Ter Kuile
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Eric Ochomo
- Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578, Kisumu, Kenya
| | - Stephen Munga
- Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578, Kisumu, Kenya
| | - Aaron M Samuels
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Kiambo Njagi
- Kenya National Malaria Control Programme (NMCP), Ministry of Health, PO Box 19982, Kenyatta National Hospital, Nairobi, 00202, Kenya
| | - James Maas
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Robert T Perry
- The United States Presidents Malaria Initiative (PMI), US Embassy Nairobi, United Nations Avenue, Nairobi, Kenya
| | - Christen Fornadel
- The United States Presidents Malaria Initiative (PMI), US Agency for International Development, Washington, DC, USA
| | - Martin J Donnelly
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Richard M Oxborough
- PMI VectorLink Project, Abt Associates 6130 Executive Blv, Rockville, MD, 20852, USA
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33
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Tomlinson S, Carrington Yates H, Oruni A, Njoroge H, Weetman D, Donnelly MJ, Hof AEV. Open source 3D printable replacement parts for the WHO insecticide susceptibility bioassay system. Parasit Vectors 2019; 12:539. [PMID: 31727146 PMCID: PMC6857140 DOI: 10.1186/s13071-019-3789-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 11/04/2019] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Malaria vector control and research rely heavily on monitoring mosquito populations for the development of resistance to public health insecticides. One standard method for determining resistance in adult mosquito populations is the World Health Organization test (WHO bioassay). The WHO bioassay kit consists of several acrylic pieces that are assembled into a unit. Parts of the kit commonly break, reducing the capacity of insectaries to carry out resistance profiling. Since there is at present only a single supplier for the test kits, replacement parts can be hard to procure in a timely fashion. METHODS Using computer-aided design software and widely available polylactic acid (PLA) filament as a printing material, we 3D designed and printed replacement parts for the WHO bioassay system. We conducted a comparison experiment between original WHO bioassay kits and 3D printed kits to assess congruence between results. The comparison experiment was performed on two Kenyan laboratory strains of Anopheles gambiae (s.s.), Kilifi and Mbita. Student's t-tests were used to assess significant differences between tube types. Finally, we exposed the PLA filament to common solutions used with the bioassay kit. RESULTS We were able to design and print functional replacements for each piece of the WHO bioassay kit. Replacement parts are functionally identical to and interchangeable with original WHO bioassay parts. We note no significant difference in mortality results obtained from PLA printed tubes and WHO acrylic tubes. Additionally, we observed no degradation of PLA in response to prolonged exposure times of commonly used cleaning solutions. CONCLUSIONS Our designs can be used to produce replacement parts for the WHO bioassay kit in any facility with a 3D printer, which are becoming increasingly widespread. 3D printing technologies can affordably and rapidly address equipment shortages and be used to develop bespoke equipment in laboratories.
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Affiliation(s)
- Sean Tomlinson
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | | | - Ambrose Oruni
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
- College of Veterinary Medicine, Animal Resources & Biosecurity, Makerere University, Kampala, Uganda
| | - Harun Njoroge
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
| | - David Weetman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Martin J. Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Arjen E Van’t Hof
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
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34
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Huestis DL, Dao A, Diallo M, Sanogo ZL, Samake D, Yaro AS, Ousman Y, Linton YM, Krishna A, Veru L, Krajacich BJ, Faiman R, Florio J, Chapman JW, Reynolds DR, Weetman D, Mitchell R, Donnelly MJ, Talamas E, Chamorro L, Strobach E, Lehmann T. Windborne long-distance migration of malaria mosquitoes in the Sahel. Nature 2019; 574:404-408. [PMID: 31578527 DOI: 10.1038/s41586-019-1622-4] [Citation(s) in RCA: 98] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 09/06/2019] [Indexed: 11/09/2022]
Abstract
Over the past two decades efforts to control malaria have halved the number of cases globally, yet burdens remain high in much of Africa and the elimination of malaria has not been achieved even in areas where extreme reductions have been sustained, such as South Africa1,2. Studies seeking to understand the paradoxical persistence of malaria in areas in which surface water is absent for 3-8 months of the year have suggested that some species of Anopheles mosquito use long-distance migration3. Here we confirm this hypothesis through aerial sampling of mosquitoes at 40-290 m above ground level and provide-to our knowledge-the first evidence of windborne migration of African malaria vectors, and consequently of the pathogens that they transmit. Ten species, including the primary malaria vector Anopheles coluzzii, were identified among 235 anopheline mosquitoes that were captured during 617 nocturnal aerial collections in the Sahel of Mali. Notably, females accounted for more than 80% of all of the mosquitoes that we collected. Of these, 90% had taken a blood meal before their migration, which implies that pathogens are probably transported over long distances by migrating females. The likelihood of capturing Anopheles species increased with altitude (the height of the sampling panel above ground level) and during the wet seasons, but variation between years and localities was minimal. Simulated trajectories of mosquito flights indicated that there would be mean nightly displacements of up to 300 km for 9-h flight durations. Annually, the estimated numbers of mosquitoes at altitude that cross a 100-km line perpendicular to the prevailing wind direction included 81,000 Anopheles gambiae sensu stricto, 6 million A. coluzzii and 44 million Anopheles squamosus. These results provide compelling evidence that millions of malaria vectors that have previously fed on blood frequently migrate over hundreds of kilometres, and thus almost certainly spread malaria over these distances. The successful elimination of malaria may therefore depend on whether the sources of migrant vectors can be identified and controlled.
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Affiliation(s)
- Diana L Huestis
- Laboratory of Malaria and Vector Research, NIAID, NIH, Rockville, MD, USA
| | - Adama Dao
- Malaria Research and Training Center (MRTC), Faculty of Medicine, Pharmacy and Odonto-stomatology, University of Bamako, Bamako, Mali
| | - Moussa Diallo
- Malaria Research and Training Center (MRTC), Faculty of Medicine, Pharmacy and Odonto-stomatology, University of Bamako, Bamako, Mali
| | - Zana L Sanogo
- Malaria Research and Training Center (MRTC), Faculty of Medicine, Pharmacy and Odonto-stomatology, University of Bamako, Bamako, Mali
| | - Djibril Samake
- Malaria Research and Training Center (MRTC), Faculty of Medicine, Pharmacy and Odonto-stomatology, University of Bamako, Bamako, Mali
| | - Alpha S Yaro
- Malaria Research and Training Center (MRTC), Faculty of Medicine, Pharmacy and Odonto-stomatology, University of Bamako, Bamako, Mali.,Faculte des Sciences et Techniques, Universite des Sciences des Techniques et des Technologies de Bamako (FSTUSTTB), Bamako, Mali
| | - Yossi Ousman
- Malaria Research and Training Center (MRTC), Faculty of Medicine, Pharmacy and Odonto-stomatology, University of Bamako, Bamako, Mali
| | - Yvonne-Marie Linton
- Walter Reed Biosystematics Unit, Smithsonian Institution Museum Support Center, Suitland, MD, USA.,Department of Entomology, Smithsonian Institution, National Museum of Natural History, Washington, DC, USA
| | - Asha Krishna
- Laboratory of Malaria and Vector Research, NIAID, NIH, Rockville, MD, USA
| | - Laura Veru
- Laboratory of Malaria and Vector Research, NIAID, NIH, Rockville, MD, USA
| | | | - Roy Faiman
- Laboratory of Malaria and Vector Research, NIAID, NIH, Rockville, MD, USA
| | - Jenna Florio
- Laboratory of Malaria and Vector Research, NIAID, NIH, Rockville, MD, USA
| | - Jason W Chapman
- Centre for Ecology and Conservation, University of Exeter, Penryn, UK.,College of Plant Protection, Nanjing Agricultural University, Nanjing, China.,Environment and Sustainability Institute, University of Exeter, Penryn, UK
| | - Don R Reynolds
- Natural Resources Institute, University of Greenwich, Chatham, UK.,Rothamsted Research, Harpenden, UK
| | - David Weetman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Reed Mitchell
- Walter Reed Biosystematics Unit, Smithsonian Institution Museum Support Center, Suitland, MD, USA
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Elijah Talamas
- Systematic Entomology Laboratory - ARS, USDA, Smithsonian Institution National Museum of Natural History, Washington, DC, USA.,Florida Department of Agriculture and Consumer Services, Department of Plant Industry, Gainesville, FL, USA
| | - Lourdes Chamorro
- Department of Entomology, Smithsonian Institution, National Museum of Natural History, Washington, DC, USA.,Systematic Entomology Laboratory - ARS, USDA, Smithsonian Institution National Museum of Natural History, Washington, DC, USA
| | - Ehud Strobach
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, USA.,Global Modeling and Assimilation Office, NASA GSFC, Greenbelt, MD, USA
| | - Tovi Lehmann
- Laboratory of Malaria and Vector Research, NIAID, NIH, Rockville, MD, USA.
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Lucas ER, Rockett KA, Lynd A, Essandoh J, Grisales N, Kemei B, Njoroge H, Hubbart C, Rippon EJ, Morgan J, Van't Hof AE, Ochomo EO, Kwiatkowski DP, Weetman D, Donnelly MJ. A high throughput multi-locus insecticide resistance marker panel for tracking resistance emergence and spread in Anopheles gambiae. Sci Rep 2019; 9:13335. [PMID: 31527637 PMCID: PMC6746726 DOI: 10.1038/s41598-019-49892-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 09/03/2019] [Indexed: 01/11/2023] Open
Abstract
The spread of resistance to insecticides in disease-carrying mosquitoes poses a threat to the effectiveness of control programmes, which rely largely on insecticide-based interventions. Monitoring mosquito populations is essential, but obtaining phenotypic measurements of resistance is laborious and error-prone. High-throughput genotyping offers the prospect of quick and repeatable estimates of resistance, while also allowing resistance markers to be tracked and studied. To demonstrate the potential of highly-mulitplexed genotypic screening for measuring resistance-association of mutations and tracking their spread, we developed a panel of 28 known or putative resistance markers in the major malaria vector Anopheles gambiae, which we used to screen mosquitoes from a wide swathe of Sub-Saharan Africa (Burkina Faso, Ghana, Democratic Republic of Congo (DRC) and Kenya). We found resistance association in four markers, including a novel mutation in the detoxification gene Gste2 (Gste2-119V). We also identified a duplication in Gste2 combining a resistance-associated mutation with its wild-type counterpart, potentially alleviating the costs of resistance. Finally, we describe the distribution of the multiple origins of kdr resistance, finding unprecedented diversity in the DRC. This panel represents the first step towards a quantitative genotypic model of insecticide resistance that can be used to predict resistance status in An. gambiae.
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Affiliation(s)
- Eric R Lucas
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
| | - Kirk A Rockett
- Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK
| | - Amy Lynd
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - John Essandoh
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.,Department of Wildlife and Entomology, University of Cape Coast, Cape Coast, Ghana
| | - Nelson Grisales
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.,Abt Associates, 6130 Executive BLVD, Rockville, MD, United States
| | - Brigid Kemei
- Kenya Medical Research Institute (KEMRI), Centre for Global Health Research, Kisumu, Kenya
| | - Harun Njoroge
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Christina Hubbart
- Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK
| | - Emily J Rippon
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - John Morgan
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Arjen E Van't Hof
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Eric O Ochomo
- Kenya Medical Research Institute (KEMRI), Centre for Global Health Research, Kisumu, Kenya
| | - Dominic P Kwiatkowski
- Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK.,Wellcome Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - David Weetman
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Martin J Donnelly
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.,Wellcome Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
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36
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Lucas ER, Miles A, Harding NJ, Clarkson CS, Lawniczak MKN, Kwiatkowski DP, Weetman D, Donnelly MJ. Whole-genome sequencing reveals high complexity of copy number variation at insecticide resistance loci in malaria mosquitoes. Genome Res 2019; 29:1250-1261. [PMID: 31345938 PMCID: PMC6673711 DOI: 10.1101/gr.245795.118] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 06/26/2019] [Indexed: 01/16/2023]
Abstract
Polymorphisms in genetic copy number can influence gene expression, coding sequence, and zygosity, making them powerful actors in the evolutionary process. Copy number variants (CNVs) are however understudied, being more difficult to detect than single-nucleotide polymorphisms. We take advantage of the intense selective pressures on the major malaria vector Anopheles gambiae, caused by the widespread use of insecticides for malaria control, to investigate the role of CNVs in the evolution of insecticide resistance. Using the whole-genome sequencing data from 1142 samples in the An. gambiae 1000 genomes project, we identified 250 gene-containing CNVs, encompassing a total of 267 genes of which 28 were in gene families linked to metabolic insecticide resistance, representing significant enrichment of these families. The five major gene clusters for metabolic resistance all contained CNVs, with 44 different CNVs being found across these clusters and multiple CNVs frequently covering the same genes. These 44 CNVs are widespread (45% of individuals carry at least one of them) and have been spreading through positive selection, indicated by their high local frequencies and extended haplotype homozygosity. Our results demonstrate the importance of CNVs in the response to selection, highlighting the urgent need to identify the contribution of each CNV to insecticide resistance and to track their spread as the use of insecticides in malaria endemic countries intensifies and as the operational deployment of next-generation bed nets targeting metabolic resistance gathers pace. Our detailed descriptions of CNVs found across the species range provide the tools to do so.
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Affiliation(s)
- Eric R Lucas
- Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom
| | - Alistair Miles
- Wellcome Sanger Institute, Hinxton, Cambridge CB10 1SA, United Kingdom.,Big Data Institute, University of Oxford, Li Ka Shing Centre for Health Information and Discovery, Oxford OX3 7LF, United Kingdom
| | - Nicholas J Harding
- Big Data Institute, University of Oxford, Li Ka Shing Centre for Health Information and Discovery, Oxford OX3 7LF, United Kingdom
| | - Chris S Clarkson
- Wellcome Sanger Institute, Hinxton, Cambridge CB10 1SA, United Kingdom
| | | | - Dominic P Kwiatkowski
- Wellcome Sanger Institute, Hinxton, Cambridge CB10 1SA, United Kingdom.,Big Data Institute, University of Oxford, Li Ka Shing Centre for Health Information and Discovery, Oxford OX3 7LF, United Kingdom
| | - David Weetman
- Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom
| | - Martin J Donnelly
- Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom.,Wellcome Sanger Institute, Hinxton, Cambridge CB10 1SA, United Kingdom
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37
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Moyes CL, Wiebe A, Gleave K, Trett A, Hancock PA, Padonou GG, Chouaïbou MS, Sovi A, Abuelmaali SA, Ochomo E, Antonio-Nkondjio C, Dengela D, Kawada H, Dabire RK, Donnelly MJ, Mbogo C, Fornadel C, Coleman M. Analysis-ready datasets for insecticide resistance phenotype and genotype frequency in African malaria vectors. Sci Data 2019; 6:121. [PMID: 31308378 PMCID: PMC6629700 DOI: 10.1038/s41597-019-0134-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 06/19/2019] [Indexed: 12/19/2022] Open
Abstract
The impact of insecticide resistance in malaria vectors is poorly understood and quantified. Here a series of geospatial datasets for insecticide resistance in malaria vectors are provided, so that trends in resistance in time and space can be quantified, and the impact of resistance found in wild populations on malaria transmission in Africa can be assessed. Specifically, data have been collated and geopositioned for the prevalence of insecticide resistance, as measured by standard bioassays, in representative samples of individual species or species complexes. Data are provided for the Anopheles gambiae species complex, the Anopheles funestus subgroup, and for nine individual vector species. Data are also given for common genetic markers of resistance to support analyses of whether these markers can improve the ability to monitor resistance in low resource settings. Allele frequencies for known resistance-associated markers in the Voltage-gated sodium channel (Vgsc) are provided. In total, eight analysis-ready, standardised, geopositioned datasets encompassing over 20,000 African mosquito collections between 1957 and 2017 are released.
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Affiliation(s)
- Catherine L Moyes
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX1 7LF, UK.
| | - Antoinette Wiebe
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX1 7LF, UK
| | - Katherine Gleave
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool L1, UK
| | - Anna Trett
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool L1, UK
| | - Penelope A Hancock
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX1 7LF, UK
| | - Germain Gil Padonou
- Centre de Recherche Entomologique de Cotonou (CREC), 06BP2604, Cotonou, Benin
| | - Mouhamadou S Chouaïbou
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01BP1303, Abj 01, Abidjan, Côte d'Ivoire
| | - Arthur Sovi
- Centre de Recherche Entomologique de Cotonou (CREC), 06BP2604, Cotonou, Benin
- Faculty of Agronomy, University of Parakou, BP123, Parakou, Benin
| | - Sara A Abuelmaali
- Department of Medical Entomology, National Public Health Laboratory, Federal Ministry of Health, Khartoum, Sudan
| | - Eric Ochomo
- Kenya Medical Research Institute, Center for Global Health Research, Kisumu, Kenya
| | - Christophe Antonio-Nkondjio
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon
| | - Dereje Dengela
- U.S. PMI VectorLink Project, Abt Associates, 6130 Executive Boulevard, Rockville, MD, 20852, USA
| | - Hitoshi Kawada
- Department of Vector Ecology and Environment, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | - Roch K Dabire
- Department of Medical Biology and Public Health, Institut de Recherche en Science de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool L1, UK
| | - Charles Mbogo
- KEMRI Centre for Geographic Medicine Research-Coast, P.O Box 230-80108, Kilifi, Kenya
- KEMRI-Wellcome Trust Research Program, P.O Box 43640-00100, Nairobi, Kenya
| | - Christen Fornadel
- US President's Malaria Initiative, US Agency for International Development, Washington, DC, USA
| | - Michael Coleman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool L1, UK
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38
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Staedke SG, Kamya MR, Dorsey G, Maiteki-Sebuguzi C, Gonahasa S, Yeka A, Lynd A, Opigo J, Hemingway J, Donnelly MJ. LLIN Evaluation in Uganda Project (LLINEUP) - Impact of long-lasting insecticidal nets with, and without, piperonyl butoxide on malaria indicators in Uganda: study protocol for a cluster-randomised trial. Trials 2019; 20:321. [PMID: 31159887 PMCID: PMC6547536 DOI: 10.1186/s13063-019-3382-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 04/24/2019] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Long-lasting insecticidal nets (LLINs) are a key malaria control intervention, but their effectiveness is threatened by resistance to pyrethroid insecticides. Some new LLINs combine pyrethroids with piperonyl butoxide (PBO), a synergist that can overcome P450-based metabolic resistance to pyrethroids in mosquitoes. In 2017-2018, the Ugandan Ministry of Health distributed LLINs with and without PBO through a national mass-distribution campaign, providing a unique opportunity to rigorously evaluate PBO LLINs across different epidemiological settings. METHODS/DESIGN Together with the Ministry of Health, we embedded a cluster-randomised trial to evaluate the impact of LLINs delivered in the 2017-2018 national campaign. A total of 104 clusters (health sub-districts) in Eastern and Western Uganda were involved, covering 48 of 121 (40%) districts. Using adaptive randomisation driven by the number of LLINs available, clusters were assigned to receive one of four types of LLINs, including two brands with PBO: 1) PermaNet 3.0 (n = 32) and 2) Olyset Plus (n = 20); and two without PBO: 3) PermaNet 2.0 (n = 37) and 4) Olyset Net (n = 15). We are conducting cross-sectional community surveys in 50 randomly selected households per cluster (5200 households per survey) and entomological surveillance for insecticide resistance in up to 10 randomly selected households enrolled in the community surveys per cluster (1040 households per survey) at baseline and 6, 12, and 18 months after LLIN distribution. Net durability and bio-efficacy will be assessed in 400 nets withdrawn from households with replacement at 12 months. The primary trial outcome is parasite prevalence as measured by microscopy in children aged 2-10 years in the follow-up surveys. DISCUSSION PBO LLINs are a promising new tool to reduce the impact of pyrethroid resistance on malaria control. The World Health Organization has issued a preliminary endorsement of PBO LLINs, but additional epidemiological evidence of the effect of PBO LLINs is urgently needed. The results of this innovative, large-scale trial embedded within a routine national distribution campaign will make an important contribution to the malaria control policy in Uganda and throughout Africa, where pyrethroid resistance in malaria vectors has increased dramatically. This model of evaluation could be a paradigm for future assessment of malaria control interventions. TRIAL REGISTRATION ISRCTN, ISRCTN17516395 . Registered on 14 February 2017. WORLD HEALTH ORGANIZATION TRIAL REGISTRATION DATA SET See Additional file 1.
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Affiliation(s)
- Sarah G. Staedke
- London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT UK
| | - Moses R. Kamya
- Makerere University College of Health Sciences, Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Grant Dorsey
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94110 USA
| | - Catherine Maiteki-Sebuguzi
- National Malaria Control Division, Uganda Ministry of Health, Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Samuel Gonahasa
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Adoke Yeka
- Makerere University School of Public Health, Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Amy Lynd
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA UK
| | - Jimmy Opigo
- National Malaria Control Division, Uganda Ministry of Health, Kampala, Uganda
| | - Janet Hemingway
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA UK
| | - Martin J. Donnelly
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA UK
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39
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Sedda L, Lucas ER, Djogbénou LS, Edi AVC, Egyir-Yawson A, Kabula BI, Midega J, Ochomo E, Weetman D, Donnelly MJ. Improved spatial ecological sampling using open data and standardization: an example from malaria mosquito surveillance. J R Soc Interface 2019; 16:20180941. [PMID: 30966952 PMCID: PMC6505554 DOI: 10.1098/rsif.2018.0941] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 03/19/2019] [Indexed: 01/05/2023] Open
Abstract
Vector-borne disease control relies on efficient vector surveillance, mostly carried out using traps whose number and locations are often determined by expert opinion rather than a rigorous quantitative sampling design. In this work we propose a framework for ecological sampling design which in its preliminary stages can take into account environmental conditions obtained from open data (i.e. remote sensing and meteorological stations) not necessarily designed for ecological analysis. These environmental data are used to delimit the area into ecologically homogeneous strata. By employing Bayesian statistics within a model-based sampling design, the traps are deployed among the strata using a mixture of random and grid locations which allows balancing predictions and model-fitting accuracies. Sample sizes and the effect of ecological strata on sample sizes are estimated from previous mosquito sampling campaigns open data. Notably, we found that a configuration of 30 locations with four households each (120 samples) will have a similar accuracy in the predictions of mosquito abundance as 200 random samples. In addition, we show that random sampling independently from ecological strata, produces biased estimates of the mosquito abundance. Finally, we propose standardizing reporting of sampling designs to allow transparency and repetition/re-use in subsequent sampling campaigns.
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Affiliation(s)
- Luigi Sedda
- Centre for Health Information, Computation and Statistics (CHICAS), Lancaster Medical School, Lancaster University, Furness Building, Lancaster LA1 4YG, UK
| | - Eric R. Lucas
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Luc S. Djogbénou
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
- Institut Régional de Santé Publique/Université d'Abomey–Calavi, BP 384 Ouidah, Benin
| | - Ako V. C. Edi
- Centre Suisse de Recherches Scientifiques en Cote d'Ivoire, 01 BP 1303 Abidjan 01, Cote d'Ivoire
| | | | - Bilali I. Kabula
- National Institute for Medical Research (NIMR), Amani Centre, PO Box 81, Muheza, Tanzania
| | - Janet Midega
- Centre for Geographic Medicine Research, Kenya Medical Research Institute, PO Box 230, 80108 Kilifi, Kenya
| | - Eric Ochomo
- Centre for Global Health Research, Kenya Medical Research Institute, PO Box 1578 – 40100 Kisumu, Kenya
| | - David Weetman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Martin J. Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
- Wellcome Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
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40
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Lynd A, Gonahasa S, Staedke SG, Oruni A, Maiteki-Sebuguzi C, Dorsey G, Opigo J, Yeka A, Katureebe A, Kyohere M, Hemingway J, Kamya MR, Donnelly MJ. LLIN Evaluation in Uganda Project (LLINEUP): a cross-sectional survey of species diversity and insecticide resistance in 48 districts of Uganda. Parasit Vectors 2019; 12:94. [PMID: 30867018 PMCID: PMC6417037 DOI: 10.1186/s13071-019-3353-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 02/26/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Long-lasting insecticidal nets (LLINs) are the principal tool for malaria control in Africa and are presently treated with a single class of insecticide; however, increasing levels of insecticide resistance threaten their success. In response to this threat nets have been developed that incorporate the synergist, piperonyl butoxide (PBO), which inhibits the activity of cytochrome P450s which is one main mechanisms of insecticide resistance, allowing resistance to pyrethroids to be reversed. However, data on the value and cost effectiveness of these nets is lacking. A large-scale cluster randomised trial of conventional LLINs and PBO-LLINs was conducted in Uganda in 104 health sub-districts (HSDs) in 2017-2019. Prior to the mass distribution of LLINs, a baseline entomological survey was carried out, the results of which are reported herein. Ten households from each HSD were randomly selected for entomological surveillance at baseline which included household mosquito collections. RESULTS Prior to LLIN distribution entomological collections were carried out in 1029 houses across the 104 HSDs. Anopheles gambiae (s.l.) was the principal vector in all but 9 of the 71 HSDs that yielded vector species. Molecular analysis found An. gambiae (s.s.) to be the predominant vector collected. Plasmodium falciparum was detected in 5.5% of An. gambiae (s.s.) and in 4.0% of An. funestus (s.s.) examined. Infection rates of other plasmodium species (P. vivax, P. ovale and P. malariae) were lower with infection rates of 1.2% and 1.7% for An. gambiae (s.s.) and An. funestus (s.s.), respectively. The knockdown resistance (kdr) mutation Vgsc-L1014S was found at very high frequency in An. gambiae (s.s.) with the Vgsc-L1014F mutation at low frequency and the wild-type allele virtually absent. In An. arabiensis the wild-type allele was predominant. The resistance-associated alleles, Cyp4j5-L43F and Coeae1d were found at moderate frequencies which varied across the study site. Vgsc-N1575Y mutation was not found in any samples examined. CONCLUSIONS No significant differences between planned intervention arms was observed in vector densities, sporozoite infection rate or insecticide resistance marker frequency across the study site prior to the distribution of LLINs. Very high levels of kdr resistance were observed in all areas; however, the resistance-associated markers Cyp4j5-L43F and Coeae1d were found at varying frequencies across the study site which may have implications for the effectiveness of standard LLINs. Trial registration This study is registered with ISRCTN, ISRCTN17516395. Registered 14 February 2017, http://www.isrctn.com/ISRCTN17516395.
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Affiliation(s)
- Amy Lynd
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
| | - Samuel Gonahasa
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Sarah G Staedke
- London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Ambrose Oruni
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Catherine Maiteki-Sebuguzi
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda.,National Malaria Control Programme, Uganda Ministry of Health, Kampala, Uganda
| | - Grant Dorsey
- University of California, San Francisco, San Francisco, CA, 94110, USA
| | - Jimmy Opigo
- National Malaria Control Programme, Uganda Ministry of Health, Kampala, Uganda
| | - Adoke Yeka
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Agaba Katureebe
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Mary Kyohere
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Janet Hemingway
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Moses R Kamya
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Martin J Donnelly
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
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Tokponnon FT, Sissinto Y, Ogouyémi AH, Adéothy AA, Adechoubou A, Houansou T, Oke M, Kinde-Gazard D, Massougbodji A, Akogbeto MC, Cornelie S, Corbel V, Knox TB, Mnzava AP, Donnelly MJ, Kleinschmidt I, Bradley J. Implications of insecticide resistance for malaria vector control with long-lasting insecticidal nets: evidence from health facility data from Benin. Malar J 2019; 18:37. [PMID: 30744666 PMCID: PMC6371432 DOI: 10.1186/s12936-019-2656-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 01/16/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Insecticide-based interventions have averted more than 500 million malaria cases since 2000, but insecticide resistance in mosquitoes could bring about a rebound in disease and mortality. This study investigated whether insecticide resistance was associated with increased incidence of clinical malaria. METHODS In an area of southern Benin with insecticide resistance and high use of insecticide-treated nets (ITNs), malaria morbidity and insecticide resistance were measured simultaneously in 30 clusters (villages or collections of villages) multiple times over the course of 2 years. Insecticide resistance frequencies were measured using the standard World Health Organization bioassay test. Malaria morbidity was measured by cases recorded at health facilities both in the whole population using routinely collected data and in a passively followed cohort of children under 5 years old. RESULTS There was no evidence that incidence of malaria from routinely collected data was higher in clusters with resistance frequencies above the median, either in children aged under 5 (RR = 1.27 (95% CI 0.81-2.00) p = 0.276) or in individuals aged 5 or over (RR = 1.74 (95% CI 0.91-3.34) p = 0.093). There was also no evidence that incidence was higher in clusters with resistance frequencies above the median in the passively followed cohort (RR = 1.11 (0.52-2.35) p = 0.777). CONCLUSIONS This study found no association between frequency of resistance and incidence of clinical malaria in an area where ITNs are the principal form of vector control. This may be because, as other studies have shown, ITNs continue to offer some protection from malaria even in the presence of insecticide resistance. Irrespective of resistance, nets provide only partial protection so the development of improved or supplementary vector control tools is required to reduce Africa's unacceptably high malaria burden.
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Affiliation(s)
- Filémon T Tokponnon
- National Malaria Control Programme, Cotonou, Benin.,Ministry of Health, Cotonou, Benin
| | - Yolande Sissinto
- Faculté des Sciences de la Santé de l'Université d'Abomey Calavi, Cotonou, Benin
| | | | - Adicath Adéola Adéothy
- National Malaria Control Programme, Cotonou, Benin.,Faculté des Sciences de la Santé de l'Université d'Abomey Calavi, Cotonou, Benin
| | - Alioun Adechoubou
- National Malaria Control Programme, Cotonou, Benin.,Ministry of Health, Cotonou, Benin
| | | | - Mariam Oke
- National Malaria Control Programme, Cotonou, Benin.,Ministry of Health, Cotonou, Benin
| | | | - Achille Massougbodji
- Faculté des Sciences de la Santé de l'Université d'Abomey Calavi, Cotonou, Benin
| | | | - Sylvie Cornelie
- Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), Institut de Recherche pour le Développement (IRD), CNRS, University of Montpellier, Montpellier, France
| | - Vincent Corbel
- Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), Institut de Recherche pour le Développement (IRD), CNRS, University of Montpellier, Montpellier, France
| | - Tessa B Knox
- Global Malaria Programme, WHO, Geneva, Switzerland
| | | | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Immo Kleinschmidt
- MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
| | - John Bradley
- MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK.
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Keane E, Fitzgerald CW, Smyth DA, Nataraj MB, Lang E, Skinner LJ, Donnelly MJ. Drain Usage in Head and Neck Surgery: A National Survey of Thirty-five Surgeons across Ten Units. Ir Med J 2018; 111:839. [PMID: 30560635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Introduction Drain usage is commonplace in head and neck surgery. There is an increasing body of literature disputing their routine placement in certain procedures. The aim of this study is to explore modern-day practice in terms of drain usage and the use of haemostatic agents. Methods A simple questionnaire was devised and sent to 35 ENT Surgeons across 10 units nationally. Results There was an overall response rate of 77.1% (n=27). There was considerable heterogeneity amongst surgeons in terms of indication for insertion, how the decision is made to remove the drain and if any alternative/adjunctive haemostatic agents are being used. Discussion The management of drains is poorly defined and guidelines are lacking. With increased pressure on resources, the risk of infection and discomfort to the patient, further reflection is required to evaluate if careful patient selection rather than habitual drain insertion in every case is more appropriate.
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Affiliation(s)
- E Keane
- University Hospital Waterford, Dunmore Road, Co. Waterford
| | - C W Fitzgerald
- University Hospital Waterford, Dunmore Road, Co. Waterford
| | - D A Smyth
- University Hospital Waterford, Dunmore Road, Co. Waterford
| | - M B Nataraj
- University Hospital Waterford, Dunmore Road, Co. Waterford
| | - E Lang
- University Hospital Waterford, Dunmore Road, Co. Waterford
| | - L J Skinner
- University Hospital Waterford, Dunmore Road, Co. Waterford
| | - M J Donnelly
- University Hospital Waterford, Dunmore Road, Co. Waterford
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43
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Dong X, Chaisiri K, Xia D, Armstrong SD, Fang Y, Donnelly MJ, Kadowaki T, McGarry JW, Darby AC, Makepeace BL. Genomes of trombidid mites reveal novel predicted allergens and laterally transferred genes associated with secondary metabolism. Gigascience 2018; 7:5160133. [PMID: 30445460 PMCID: PMC6275457 DOI: 10.1093/gigascience/giy127] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 10/18/2018] [Indexed: 12/21/2022] Open
Abstract
Background Trombidid mites have a unique life cycle in which only the larval stage is ectoparasitic. In the superfamily Trombiculoidea ("chiggers"), the larvae feed preferentially on vertebrates, including humans. Species in the genus Leptotrombidium are vectors of a potentially fatal bacterial infection, scrub typhus, that affects 1 million people annually. Moreover, chiggers can cause pruritic dermatitis (trombiculiasis) in humans and domesticated animals. In the Trombidioidea (velvet mites), the larvae feed on other arthropods and are potential biological control agents for agricultural pests. Here, we present the first trombidid mites genomes, obtained both for a chigger, Leptotrombidium deliense, and for a velvet mite, Dinothrombium tinctorium. Results Sequencing was performed using Illumina technology. A 180 Mb draft assembly for D. tinctorium was generated from two paired-end and one mate-pair library using a single adult specimen. For L. deliense, a lower-coverage draft assembly (117 Mb) was obtained using pooled, engorged larvae with a single paired-end library. Remarkably, both genomes exhibited evidence of ancient lateral gene transfer from soil-derived bacteria or fungi. The transferred genes confer functions that are rare in animals, including terpene and carotenoid synthesis. Thirty-seven allergenic protein families were predicted in the L. deliense genome, of which nine were unique. Preliminary proteomic analyses identified several of these putative allergens in larvae. Conclusions Trombidid mite genomes appear to be more dynamic than those of other acariform mites. A priority for future research is to determine the biological function of terpene synthesis in this taxon and its potential for exploitation in disease control.
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Affiliation(s)
- Xiaofeng Dong
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom.,Department of Biological Sciences, Xi'an Jiaotong-Liverpool University, Suzhou 215123, China.,School of Life Sciences, Jiangsu Normal University, Xuzhou 221116, China.,Institute of Infection & Global Health, University of Liverpool, L3 5RF, United Kingdom
| | - Kittipong Chaisiri
- Institute of Infection & Global Health, University of Liverpool, L3 5RF, United Kingdom.,Faculty of Tropical Medicine, Mahidol University, Ratchathewi Bangkok 10400, Thailand
| | - Dong Xia
- Institute of Infection & Global Health, University of Liverpool, L3 5RF, United Kingdom.,The Royal Veterinary College, London NW1 0TU, United Kingdom
| | - Stuart D Armstrong
- Institute of Infection & Global Health, University of Liverpool, L3 5RF, United Kingdom
| | - Yongxiang Fang
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom
| | - Tatsuhiko Kadowaki
- Department of Biological Sciences, Xi'an Jiaotong-Liverpool University, Suzhou 215123, China
| | - John W McGarry
- Institute of Veterinary Science, University of Liverpool, Liverpool L3 5RP, United Kingdom
| | - Alistair C Darby
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Benjamin L Makepeace
- Institute of Infection & Global Health, University of Liverpool, L3 5RF, United Kingdom
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44
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Lynd A, Oruni A, Van't Hof AE, Morgan JC, Naego LB, Pipini D, O'Kines KA, Bobanga TL, Donnelly MJ, Weetman D. Insecticide resistance in Anopheles gambiae from the northern Democratic Republic of Congo, with extreme knockdown resistance (kdr) mutation frequencies revealed by a new diagnostic assay. Malar J 2018; 17:412. [PMID: 30400885 PMCID: PMC6219172 DOI: 10.1186/s12936-018-2561-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 10/30/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Mutations in the voltage-gated sodium channel at codon 1014 confer knock-down resistance (kdr) to pyrethroids in a wide range of insects. Anopheles gambiae exhibits two mutant alleles at codon 1014, serine and phenylalanine; and both are now widespread across Africa. Existing screening methods only allow for one resistant allele to be detected per assay. A new locked nucleic acid (LNA) qPCR assay was developed for the simultaneous detection of both mutant alleles and the wild type allele in a single assay. This tri-allelic detection assay was assessed as part of a study of the insecticide resistance in An. gambiae sensu stricto (s.s.) in the previously un-sampled area of Nord Ubangi, Democratic Republic of the Congo. METHODS Samples from three sites were tested for insecticide susceptibility using WHO bioassays, with and without the synergist PBO preceding pyrethroid exposures, and were subsequently analysed for frequency and resistance-association of the Vgsc-1014 and Vgsc-N1575Y mutations. Results from the LNA-kdr 1014 assay were compared to results from standard TaqMan-kdr assays. RESULTS Anopheles gambiae sensu lato (s.l.) was by far the predominant vector captured (84%), with only low frequencies of Anopheles funestus s.l. (9%) detected in Nord Ubangi. Molecular identification found An. gambiae s.s. to be the principal vector (99%) although Anopheles coluzzii was detected at very low frequency. Anopheles gambiae were susceptible to the carbamate insecticide bendiocarb, but resistant to DDT and to the pyrethroids permethrin and deltamethrin. Susceptibility to both pyrethroids was partially restored with prior exposure to PBO suggesting likely involvement of metabolic resistance. Anopheles gambiae s.s. was homozygous for kdr resistant alleles with both the L1014F and L1014S mutations present, and the N1575Y polymorphism was present at low frequency. The LNA-kdr assay simultaneously detected both resistant alleles and gave results entirely consistent with those from the two TaqMan-kdr assays. CONCLUSION This study provides rare data on insecticide resistance and mechanisms in Anopheles from the centre of Africa, with the first detection of N1575Y. Nord Ubangi populations of An. gambiae s.s. show insecticide resistance mediated by both metabolic mechanisms and Vgsc mutations. The LNA-kdr assay is particularly suitable for use in populations in which both 1014S and 1014F kdr alleles co-occur and provides robust results, with higher throughput and at a quarter of the cost of TaqMan assays.
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Affiliation(s)
- Amy Lynd
- Liverpool School of Tropical Medicine, Liverpool, UK.
| | - Ambrose Oruni
- Liverpool School of Tropical Medicine, Liverpool, UK
| | | | - John C Morgan
- Liverpool School of Tropical Medicine, Liverpool, UK
| | - Leon Bwazumo Naego
- Avenue de l'infirmerie, Quartier Yola Bokonzo, Gemena, Sud Ubangi, Democratic Republic of Congo
| | | | | | | | | | - David Weetman
- Liverpool School of Tropical Medicine, Liverpool, UK
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45
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Abong'o B, Yu X, Donnelly MJ, Geier M, Gibson G, Gimnig J, Ter Kuile F, Lobo NF, Ochomo E, Munga S, Ombok M, Samuels A, Torr SJ, Hawkes FM. Host Decoy Trap (HDT) with cattle odour is highly effective for collection of exophagic malaria vectors. Parasit Vectors 2018; 11:533. [PMID: 30318015 PMCID: PMC6191991 DOI: 10.1186/s13071-018-3099-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 09/05/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND As currently implemented, malaria vector surveillance in sub-Saharan Africa targets endophagic and endophilic mosquitoes, leaving exophagic (outdoor blood-feeding) mosquitoes underrepresented. We evaluated the recently developed host decoy trap (HDT) and compared it to the gold standard, human landing catch (HLC), in a 3 × 3 Latin square study design outdoors in western Kenya. HLCs are considered to represent the natural range of Anopheles biting-behaviour compared to other sampling tools, and therefore, in principle, provide the most reliable profile of the biting population transmitting malaria. The HDT incorporates the main host stimuli that attract blood-meal seeking mosquitoes and can be baited with the odours of live hosts. RESULTS Numbers and species diversity of trapped mosquitoes varied significantly between HLCs and HDTs baited with human (HDT-H) or cattle (HDT-C) odour, revealing important differences in behaviour of Anopheles species. In the main study in Kisian, the HDT-C collected a nightly mean of 43.2 (95% CI: 26.7-69.8) Anopheles, compared to 5.8 (95% CI: 4.1-8.2) in HLC, while HDT-H collected 0.97 (95% CI: 0.4-2.1), significantly fewer than the HLC. Significantly higher proportions of An. arabiensis were caught in HDT-Cs (0.94 ± 0.01; SE) and HDT-Hs (0.76 ± 0.09; SE) than in HLCs (0.45 ± 0.05; SE) per trapping night. The proportion of An. gambiae (s.s.) was highest in HLC (0.55 ± 0.05; SE) followed by HDT-H (0.20 ± 0.09; SE) and least in HDT-C (0.06 ± 0.01; SE). An unbaited HDT placed beside locales where cattle are usually corralled overnight caught mostly An. arabiensis with proportions of 0.97 ± 0.02 and 0.80 ± 0.2 relative to the total anopheline catch in the presence and absence of cattle, respectively. A mean of 10.4 (95% CI: 2.0-55.0) Anopheles/night were trapped near cattle, compared to 0.4 (95% CI: 0.1-1.7) in unbaited HDT away from hosts. CONCLUSIONS The capability of HDTs to combine host odours, heat and visual stimuli to simulate a host provides the basis of a system to sample human- and cattle-biting mosquitoes. HDT-C is particularly effective for collecting An. arabiensis outdoors. The HDT offers the prospect of a system to monitor and potentially control An. arabiensis and other outdoor-biting mosquitoes more effectively.
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Affiliation(s)
- Bernard Abong'o
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK. .,Centre for Global Health Research, Kenya Medical Research Institute, PO Box 1578-40100, Kisumu, Kenya. .,Abt Associates Inc. PMI-VectorLink Kenya, Whitehouse, Milimani, Kisumu, Ojijo Oteko Road, P.O. Box 895-40123, Kisumu, Kenya.
| | - Xiaoyu Yu
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Martin J Donnelly
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | | | - Gabriella Gibson
- Natural Resources Institute, University of Greenwich at Medway, Chatham Maritime, Kent, ME4 4TB, UK
| | - John Gimnig
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Feiko Ter Kuile
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Neil F Lobo
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Eric Ochomo
- Centre for Global Health Research, Kenya Medical Research Institute, PO Box 1578-40100, Kisumu, Kenya
| | - Stephen Munga
- Centre for Global Health Research, Kenya Medical Research Institute, PO Box 1578-40100, Kisumu, Kenya
| | - Maurice Ombok
- Centre for Global Health Research, Kenya Medical Research Institute, PO Box 1578-40100, Kisumu, Kenya
| | - Aaron Samuels
- Centers for Disease Control and Prevention, Kisian Campus, Off Busia Road, P O Box 1578, Kisumu, 40100, Kenya
| | - Stephen J Torr
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Frances M Hawkes
- Natural Resources Institute, University of Greenwich at Medway, Chatham Maritime, Kent, ME4 4TB, UK
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Wilson AL, Pinder M, Bradley J, Donnelly MJ, Hamid-Adiamoh M, Jarju LBS, Jawara M, Jeffries D, Kandeh B, Rippon EJ, Salami K, D'Alessandro U, Lindsay SW. Correction to: Emergence of knock-down resistance in the Anopheles gambiae complex in the Upper River Region, The Gambia, and its relationship with malaria infection in children. Malar J 2018; 17:227. [PMID: 29879981 PMCID: PMC5992667 DOI: 10.1186/s12936-018-2374-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Affiliation(s)
| | - Margaret Pinder
- Durham University, Durham, UK.,Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia
| | - John Bradley
- London School of Hygiene and Tropical Medicine, London, UK
| | | | - Majidah Hamid-Adiamoh
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia
| | | | - Musa Jawara
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia
| | - David Jeffries
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia
| | - Ballah Kandeh
- National Malaria Control Programme, Banjul, The Gambia
| | | | - Kolawole Salami
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia
| | - Umberto D'Alessandro
- London School of Hygiene and Tropical Medicine, London, UK.,Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia
| | - Steven W Lindsay
- Durham University, Durham, UK.,London School of Hygiene and Tropical Medicine, London, UK
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Wilson AL, Pinder M, Bradley J, Donnelly MJ, Hamid-Adiamoh M, Jarju LBS, Jawara M, Jeffries D, Kandeh B, Rippon EJ, Salami K, D'Alessandro U, Lindsay SW. Emergence of knock-down resistance in the Anopheles gambiae complex in the Upper River Region, The Gambia, and its relationship with malaria infection in children. Malar J 2018; 17:205. [PMID: 29776361 PMCID: PMC5960171 DOI: 10.1186/s12936-018-2348-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 05/07/2018] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Insecticide resistance threatens malaria control in sub-Saharan Africa. Knockdown resistance to pyrethroids and organochlorines in Anopheles gambiae sensu lato (s.l.) is commonly caused by mutations in the gene encoding a voltage-gated sodium channel which is the target site for the insecticide. The study aimed to examine risk factors for knockdown resistance in An. gambiae s.l. and its relationship with malaria infection in children in rural Gambia. Point mutations at the Vgsc-1014 locus, were measured in An. gambiae s.l. during a 2-year trial. Cross-sectional surveys were conducted at the end of the transmission season to measure malaria infection in children aged 6 months-14 years. RESULTS Whilst few Anopheles arabiensis and Anopheles coluzzii had Vgsc-1014 mutations, the proportion of An. gambiae sensu stricto (s.s.) mosquitoes homozygous for the Vgsc-1014F mutation increased from 64.8 to 90.9% during the study. The Vgsc-1014S or 1014F mutation was 80% higher in 2011 compared to 2010, and 27% higher in the villages with indoor residual spraying compared to those without. An increase in the proportion of An. gambiae s.l. mosquitoes with homozygous Vgsc-1014F mutations and an increase in the proportion of An. gambiae s.s. in a cluster were each associated with increased childhood malaria infection. Homozygous Vgsc-1014F mutations were, however, most common in An. gambiae s.s. and almost reached saturation during the study meaning that the two variables were colinear. CONCLUSIONS As a result of colinearity between homozygous Vgsc-1014F mutations and An. gambiae s.s., it was not possible to determine whether insecticide resistance or species composition increased the risk of childhood malaria infection.
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Affiliation(s)
| | - Margaret Pinder
- Durham University, Durham, UK.,Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia
| | - John Bradley
- London School of Hygiene and Tropical Medicine, London, UK
| | | | - Majidah Hamid-Adiamoh
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia
| | | | - Musa Jawara
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia
| | - David Jeffries
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia
| | - Ballah Kandeh
- National Malaria Control Programme, Banjul, The Gambia
| | | | - Kolawole Salami
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia
| | - Umberto D'Alessandro
- London School of Hygiene and Tropical Medicine, London, UK.,Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia
| | - Steven W Lindsay
- Durham University, Durham, UK.,London School of Hygiene and Tropical Medicine, London, UK
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Isaacs AT, Mawejje HD, Tomlinson S, Rigden DJ, Donnelly MJ. Genome-wide transcriptional analyses in Anopheles mosquitoes reveal an unexpected association between salivary gland gene expression and insecticide resistance. BMC Genomics 2018; 19:225. [PMID: 29587635 PMCID: PMC5870100 DOI: 10.1186/s12864-018-4605-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 03/14/2018] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND To combat malaria transmission, the Ugandan government has embarked upon an ambitious programme of indoor residual spraying (IRS) with a carbamate class insecticide, bendiocarb. In preparation for this campaign, we characterized bendiocarb resistance and associated transcriptional variation among Anopheles gambiae s.s. mosquitoes from two sites in Uganda. RESULTS Gene expression in two mosquito populations displaying some resistance to bendiocarb (95% and 79% An. gambiae s.l. WHO tube bioassay mortality in Nagongera and Kihihi, respectively) was investigated using whole-genome microarrays. Significant overexpression of several genes encoding salivary gland proteins, including D7r2 and D7r4, was detected in mosquitoes from Nagongera. In Kihihi, D7r4, two detoxification-associated genes (Cyp6m2 and Gstd3) and an epithelial serine protease were among the genes most highly overexpressed in resistant mosquitoes. Following the first round of IRS in Nagongera, bendiocarb-resistant mosquitoes were collected, and real-time quantitative PCR analyses detected significant overexpression of D7r2 and D7r4 in resistant mosquitoes. A single nucleotide polymorphism located in a non-coding transcript downstream of the D7 genes was found at a significantly higher frequency in resistant individuals. In silico modelling of the interaction between D7r4 and bendiocarb demonstrated similarity between the insecticide and serotonin, a known ligand of D7 proteins. A meta-analysis of published microarray studies revealed a recurring association between D7 expression and insecticide resistance across Anopheles species and locations. CONCLUSIONS A whole-genome microarray approach identified an association between novel insecticide resistance candidates and bendiocarb resistance in Uganda. In addition, a single nucleotide polymorphism associated with this resistance mechanism was discovered. The use of such impartial screening methods allows for discovery of resistance candidates that have no previously-ascribed function in insecticide binding or detoxification. Characterizing these novel candidates will broaden our understanding of resistance mechanisms and yield new strategies for combatting widespread insecticide resistance among malaria vectors.
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Affiliation(s)
- Alison T Isaacs
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK.
| | | | - Sean Tomlinson
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Daniel J Rigden
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK.,Malaria Programme, Wellcome Trust Sanger Institute, Cambridge, UK
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Ismail BA, Kafy HT, Sulieman JE, Subramaniam K, Thomas B, Mnzava A, Abu Kassim NF, Ahmad AH, Knox TB, Kleinschmidt I, Donnelly MJ. Temporal and spatial trends in insecticide resistance in Anopheles arabiensis in Sudan: outcomes from an evaluation of implications of insecticide resistance for malaria vector control. Parasit Vectors 2018; 11:122. [PMID: 29499751 PMCID: PMC5834846 DOI: 10.1186/s13071-018-2732-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Accepted: 02/20/2018] [Indexed: 11/10/2022] Open
Abstract
Background Long-lasting insecticidal nets (LLINs) (with pyrethroids) and indoor residual spraying (IRS) are the cornerstones of the Sudanese malaria control program. Insecticide resistance to the principal insecticides in LLINs and IRS is a major concern. This study was designed to monitor insecticide resistance in Anopheles arabiensis from 140 clusters in four malaria-endemic areas of Sudan from 2011 to 2014. All clusters received LLINs, while half (n = 70), distributed across the four regions, had additional IRS campaigns. Methods Anopheles gambiae (s.l.) mosquitoes were identified to species level using PCR techniques. Standard WHO insecticide susceptibility bioassays were carried out to detect resistance to deltamethrin (0.05%), DDT (4%) and bendiocarb (0.1%). TaqMan assays were performed on random samples of deltamethrin-resistant phenotyped and pyrethrum spray collected individuals to determine Vgsc-1014 knockdown resistance mutations. Results Anopheles arabiensis accounted for 99.9% of any anopheline species collected across all sites. Bioassay screening indicated that mosquitoes remained susceptible to bendiocarb but were resistance to deltamethrin and DDT in all areas. There were significant increases in deltamethrin resistance over the four years, with overall mean percent mortality to deltamethrin declining from 81.0% (95% CI: 77.6–84.3%) in 2011 to 47.7% (95% CI: 43.5–51.8%) in 2014. The rate of increase in phenotypic deltamethrin-resistance was significantly slower in the LLIN + IRS arm than in the LLIN-only arm (Odds ratio 1.34; 95% CI: 1.02–1.77). The frequency of Vgsc-1014F mutation varied spatiotemporally with highest frequencies in Galabat (range 0.375–0.616) and New Halfa (range 0.241–0.447). Deltamethrin phenotypic-resistance correlated with Vgsc-1014F frequency. Conclusion Combining LLIN and IRS, with different classes of insecticide, may delay pyrethroid resistance development, but the speed at which resistance develops may be area-specific. Continued monitoring is vital to ensure optimal management and control. Electronic supplementary material The online version of this article (10.1186/s13071-018-2732-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bashir Adam Ismail
- Khartoum Malaria Free Initiative, PO Box 1517, Khartoum, Khartoum State, Sudan. .,School of Biological Sciences, Universiti Sains Malaysia, 11800, Minden, Pulau Penang, Malaysia.
| | - Hmooda Toto Kafy
- School of Biological Sciences, Universiti Sains Malaysia, 11800, Minden, Pulau Penang, Malaysia.,Integrated Vector Management Unit, Federal Ministry of Health, PO Box 303, Khartoum, Sudan
| | - Jihad Eltaher Sulieman
- Sennar Malaria Research and Training Centre, Federal Ministry of Health, PO Box 303, Sennar, Sudan
| | - Krishanthi Subramaniam
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Brent Thomas
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Abraham Mnzava
- African Leaders Malaria Alliance (ALMA), 14 Kanisa Road, Corridor Area, P.O. Box 1973, Arusha, Tanzania
| | - Nur Faeza Abu Kassim
- School of Biological Sciences, Universiti Sains Malaysia, 11800, Minden, Pulau Penang, Malaysia
| | - Abu Hassan Ahmad
- School of Biological Sciences, Universiti Sains Malaysia, 11800, Minden, Pulau Penang, Malaysia
| | - Tessa B Knox
- Global Malaria Programme, World Health Organization, Geneva, Switzerland
| | - Immo Kleinschmidt
- MRC Tropical Epidemiology Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
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50
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Lehmann T, Weetman D, Huestis DL, Yaro AS, Kassogue Y, Diallo M, Donnelly MJ, Dao A. Tracing the origin of the early wet-season Anopheles coluzzii in the Sahel. Evol Appl 2017; 10:704-717. [PMID: 28717390 PMCID: PMC5511357 DOI: 10.1111/eva.12486] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 02/24/2017] [Indexed: 11/29/2022] Open
Abstract
In arid environments, the source of the malaria mosquito populations that re‐establish soon after first rains remains a puzzle and alternative explanations have been proposed. Using genetic data, we evaluated whether the early rainy season (RS) population of Anopheles coluzzii is descended from the preceding late RS generation at the same locality, consistent with dry season (DS) dormancy (aestivation), or from migrants from distant locations. Distinct predictions derived from these two hypotheses were assessed, based on variation in 738 SNPs in eleven A. coluzzii samples, including seven samples spanning 2 years in a Sahelian village. As predicted by the “local origin under aestivation hypothesis,” temporal samples from the late RS and those collected after the first rain of the following RS were clustered together, while larger genetic distances were found among samples spanning the RS. Likewise, multilocus genotype composition of samples from the end of the RS was similar across samples until the following RS, unlike samples that spanned the RS. Consistent with reproductive arrest during the DS, no genetic drift was detected between samples taken over that period, despite encompassing extreme population minima, whereas it was detected between samples spanning the RS. Accordingly, the variance in allele frequency increased with time over the RS, but not over the DS. However, not all the results agreed with aestivation. Large genetic distances separated samples taken a year apart, and during the first year, within‐sample genetic diversity declined and increased back during the late RS, suggesting a bottleneck followed by migration. The decline of genetic diversity followed by a mass distribution of insecticide‐treated nets was accompanied by a reduced mosquito density and a rise in the mutation conferring resistance to pyrethroids, indicating a bottleneck due to insecticidal selection. Overall, our results support aestivation in A. coluzzii during the DS that is accompanied by long‐distance migration in the late RS.
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Affiliation(s)
- Tovi Lehmann
- Laboratory of Malaria and Vector Research NIAID, NIH Rockville MD USA
| | - David Weetman
- Department of Vector Biology Liverpool School of Tropical Medicine Liverpool UK
| | - Diana L Huestis
- Laboratory of Malaria and Vector Research NIAID, NIH Rockville MD USA
| | - Alpha S Yaro
- Malaria Research and Training Center (MRTC) Faculty of Medicine, Pharmacy and Odonto-stomatology Bamako Mali
| | - Yaya Kassogue
- Malaria Research and Training Center (MRTC) Faculty of Medicine, Pharmacy and Odonto-stomatology Bamako Mali
| | - Moussa Diallo
- Malaria Research and Training Center (MRTC) Faculty of Medicine, Pharmacy and Odonto-stomatology Bamako Mali
| | - Martin J Donnelly
- Department of Vector Biology Liverpool School of Tropical Medicine Liverpool UK
| | - Adama Dao
- Malaria Research and Training Center (MRTC) Faculty of Medicine, Pharmacy and Odonto-stomatology Bamako Mali
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